Azerbaijan was an independent nation from 1918 to 1920 but was then incorporated into the Soviet Union. It became a constituent (union) republic in 1936. Azerbaijan declared sovereignty on Sept. 23, 1989, and independence Aug. 30, 1991.

As a result of its broken relief, drainage patterns, climatic differences, and sharply defined altitudinal zoning of vegetation, Azerbaijan is characterized by a wide variety of landscapes. More than two-fifths of its territory is taken up by lowlands, about half lies at 1,300 to 4,900 feet (400 to 1,500 metres), and areas above 4,900 feet occupy a little more than one-tenth of the total area.

The highest peaks are Bazardyuzyu (Bazardüzü; 14,652 feet 【4,466 metres】), Shakhdag, and Tufan, all part of the Greater Caucasus range, the crest of which forms part of Azerbaijan's northern boundary. Magnificent spurs and ridges, cut into by the deep gorges of mountain streams, make this part of Azerbaijan a region of great natural beauty. At the same time, it lies within a region characterized by a high degree of seismic activity.

The spurs of the Lesser Caucasus, in southwestern Azerbaijan, form the second important mountain system, which includes the Shakhdag, Murovdag, and Zangezur ranges, their summits rising to nearly 13,000 feet, and also the Karabakh Upland. The large and scenic Lake Geygyol lies at an altitude of 5,138 feet.

The southeastern part of Azerbaijan is bordered by the Talish (Talysh (Talish Mountains)) Mountains, consisting of three longitudinal ranges, with Mount Kyumyurkyoy as the highest peak (8,176 feet), and the Länkäran Lowland, along the Caspian coast. This lowland, an extension of the Kura-Aras Lowland, reaches the Iranian border near Astara.

The Kura-Aras Lowland is named for the main river, the Kura (Kür), and its tributary the Aras (Araz). The Shirvan, Milskaya, and Mugan plains are part of this lowland and have similar soils and climate. Gray soils and saline solonchaks (aridisols) and, in higher regions, gray alkaline solonetz and chestnut soils (mollisols) prevail.

A well-developed network of canals between the Kura (Kura River) and Aras rivers (Aras River) makes it possible to irrigate a major part of the lowland. The Upper Karabakh Canal, 107 miles (172 kilometres) long, provides a vital link between the Aras River and the Mingäçevir Reservoir on the Kura River. The reservoir has a surface area of 234 square miles and a maximum depth of 246 feet. The Upper Karabakh Canal alone irrigates more than 250,000 acres (100,000 hectares) of fertile land and in addition supplies the Aras River with water during dry summer periods. The Upper Shirvan Canal, the second most important canal, is 76 miles in length and also irrigates about 250,000 acres.

The dry subtropical climate of central and eastern Azerbaijan is characterized by a mild winter and a long (four to five months) and very hot summer, with temperatures averaging about 81° F (27° C) and maximum temperatures reaching 109° F (43° C).

Southeastern Azerbaijan is characterized by a humid subtropical climate with the highest precipitation in the country, some 47 to 55 inches (1,200 to 1,400 millimetres) a year, most of it falling in the cold months.

A dry continental climate, with a cold winter and a dry, hot summer, prevails in Naxçıvan at altitudes of 2,300 to 3,300 feet. Moderately warm, dry, or humid types of climate are to be found in other parts of Azerbaijan. The mountain forest zone has a moderately cold climate, while an upland tundra climate characterizes elevations of 10,000 feet and above. Frosts and heavy snowfalls make the passes at such altitudes inaccessible for three or four months of the year.

Natural vegetation zones vary according to altitude. Steppe and semidesert conditions prevail in the lowlands and the foothills of the mountain regions. The slopes of the mountains are covered with beech, oak, and pine forests. Higher up there is a zone of alpine meadows. The Länkäran region of southern Azerbaijan has evergreen vegetation and thick beech and oak forests.

In the lowlands the animal life includes gazelles, jackals, and hyenas as well as reptile and rodent species. The mountain regions are inhabited by Caucasian deer, roe deer, wild boar, brown bear, lynx, European bison (wisent), chamois, and leopard, though the latter is rare. Mild winters draw many birds to the Caspian coast, and nature reserves provide a resting home for flamingos, swans, pelicans, herons, egrets, sandpipers, and partridges.

More than half of the country's population lives in urban areas. The most densely populated region is the Abşeron Peninsula, on the western coast of the Caspian Sea. Baku, Azerbaijan's largest city and the most important industrial city in Transcaucasia, is located on this peninsula, as are other industrial towns, including Sumqayıt.

Baku is a large and attractive city situated on natural terraces running down to a gulf of the Caspian Sea. The city has a 2-mile- (3.2-kilometre-) long picturesque boulevard and many historic sites.

Other areas of dense population occur in certain lowland and foothill regions. Gäncä is the second largest town and the main urban centre of the interior.

The highest density of rural population is found in Länkäran and Masallı in the southeast. The Talysh, or Talishi—Iranian people who form the bulk of the local population—have preserved many of their old customs and traditions.

Azerbaijan has a growing and youthful population. Turkic-speaking Azerbaijanis (Azerbaijani) (Azeris) make up some four-fifths of the country's population; the remaining population comprises only small concentrations of minorities—among them, Lezgians (who speak a Caucasian language (Caucasian languages)), Russians, and Armenians. Ethnic Azerbaijanis combine in themselves the dominant Turkic strain, which arrived in Azerbaijan especially during the Oghuz Seljuq migrations of the 11th century, with mixtures of older inhabitants—Iranians and others—who had lived in Transcaucasia since ancient times. At the end of the 20th century, about 13 million Azerbaijanis lived abroad, most of them in Iran.

At the beginning of the 21st century, the population of the Azerbaijani exclave of Naxçıvan (Nakhichevan) (lying wholly within Armenia) was almost entirely ethnic Azerbaijani, whereas the enclave of Nagorno-Karabakh (lying wholly within Azerbaijan) was predominantly ethnic Armenian. In the Soviet era there were several disagreements regarding the status of the two territories' placement. After a number of reversals, the Soviet government provided that Naxçıvan was to be recognized as an Autonomous Soviet Socialist Republic (A.S.S.R.) with close ties to Azerbaijan, while Karabakh was to remain within the Azerbaijan S.S.R. but with significant autonomy. In the early 1920s the region, including its mountainous zone, was confirmed as the Nagorno-Karabakh Autonomous Oblast.

In the late 1980s, sizable Azerbaijani and Armenian populations were driven from each other's countries as a result of ethnic conflict and disputes over the Nagorno-Karabakh region. In addition, full-scale combat in the early 1990s, as well as territorial expansion by the ethnic Armenians (Armenian) within Azerbaijan, resulted in the displacement of a significant number of Azerbaijanis. Conflict between Armenians and Azerbaijanis over Nagorno-Karabakh, which persisted into the 21st century, was complicated by an official declaration of independence by the Republic of Nagorno-Karabakh in 1992 (a claim that failed to gain recognition from the international community).

The Azerbaijani language is a member of the West Oghuz group of the southwestern (Oghuz) branch of the Turkic languages. The literary tradition dates to the 14th century. The Arabic script was used until the 20th century; the Cyrillic alphabet was introduced in 1939. In 1992 the Azerbaijani government switched from the Cyrillic to the Roman alphabet as its official orthography.

Azerbaijan is predominantly a Muslim country; about three-fifths of the population are Shīʿite, and about one-fourth are Sunni (Sunnite). A very small percentage of the population are members of Russian or Armenian Orthodox churches.

Azerbaijan is a developed industrial and agrarian country. The emphasis on heavy industry has considerably expanded two traditional industries—petroleum and natural gas—but engineering, light industry, and food production are also of growing importance.

In the early 1990s Azerbaijan began a transition to a market economy. Prices of most goods were liberalized, and some state-owned enterprises were privatized. Land privatization, however, proceeded slowly.

At the beginning of the 20th century Azerbaijan was the world's leading petroleum producer, and it was also the birthplace of the oil-refining industry. In 1901, for example, Azerbaijan produced 11.4 million tons of oil, more than the United States; it accounted for more than half of world production. As the 20th century progressed, however, Azerbaijan's role in oil production decreased as the industry developed in other regions of the U.S.S.R. and elsewhere in the world.

During the 1990s exploitation of the vast oil fields under the Caspian Sea was complicated by political instability in Azerbaijan, ethnic conflict throughout the region, Russian claims on the Caspian fields, and disputes over the location of new pipelines.

Azerbaijan has other natural resources, including natural gas, iodobromide waters, lead, zinc, iron, and copper ores, nepheline syenites utilized in the production of aluminum, common salt, and a great variety of building materials, including marl, limestone, and marble.

Azerbaijan's agriculture developed considerably in the latter part of the 20th century. Almost half of the country's total area is suitable for agriculture, and some two-fifths of this is under cultivation.

Grain is the leading agricultural product, with raw cotton the second most valuable crop. Favourable conditions for grapes have contributed to the development of viticulture. Most of the grape varieties grown in Azerbaijan are used for making wine, almost all of which is exported. Other crops include vegetables (particularly early varieties), fruits, walnuts, and hazelnuts. Some districts, particularly those around the cities of Şäki, Zaqatala, and Göyçay, are—as they have been traditionally—engaged in silkworm breeding.

High commodity output is not characteristic of Azerbaijan's animal husbandry.

Azerbaijani fisheries are of particular importance because of the sturgeon of the Caspian Sea; sturgeon roe is made into internationally renowned caviar. Sturgeon stocks are being depleted, however, as a result of pollution of Caspian waters.

Azerbaijan has a diversified industrial base, with the leading branches of heavy industry—power, manufacturing, and chemical production—predominating. Branches of the processing industry, producing mineral fertilizers, gasoline, kerosene, herbicides, industrial oils, synthetic rubber, and plastics, have developed, and Sumqayıt has emerged as the major centre of this industry, as well as of ferrous metallurgy.

The country's manufacturing industries have grown considerably in the late 20th century. Azerbaijan manufactures equipment for the oil and gas industry, electrical equipment of all kinds, and many appliances and instruments. This type of industry is located mostly in Baku, Gäncä, and Mingäçevir.

Light industrial manufactures include cotton and woolen textiles, knitwear, traditional household items and souvenirs, footwear, and other consumer goods. Şäki, Xankändi, Gäncä, Mingäçevir, and Baku are the main centres of this industry. Food-processing plants are distributed fairly evenly throughout the republic.

The development of Azerbaijan's industry created a demand for fuel and power supplies. All electricity is produced at thermoelectric power stations burning fossil fuels, which have been built throughout the country.

Azerbaijan exports chemicals, machinery, food (particularly grapes and other fruits and vegetables), beverages, petroleum and natural gas, iron and steel, nonferrous metals, and other products; its imports include iron and steel, machinery, and food and beverages, particularly meat and milk. Azerbaijan's primary trading partners are Russia, Turkey, Iran, and Ukraine; the country also has trade links with Georgia, Belarus, Britain, and the Central Asian republics. Azerbaijan has no trade with Armenia because of the conflict over Nagorno-Karabakh.

Few of the rivers of Azerbaijan are navigable, and most freight—including that transported out of the country—is carried by rail and truck. Considerable portions of the rail network are electrified. The principal goods carried are oil products, building materials, timber, and grain. A major railway line traverses the Kura valley and connects Baku with Tʿbilisi and Batʿumi in Georgia. Another parallels the Caspian Sea north of Baku.

Motor transport is used extensively for both freight and passengers. Roads connect various parts of the country and are often the only means of land communication between remote mountain districts and the administrative centres and large cities.

Baku, on the Caspian, is a busy seaport, handling such goods as oil, timber, grain, and cotton. The ferry link between Baku and Türkmenbashy (also on the Caspian, in Turkmenistan) augments considerably the amount of cargo passing through Azerbaijan. Air routes connect Baku with many European and Asian cities.

The Abşeron region includes the Abşeron Peninsula and several other areas of eastern Azerbaijan. As a result of its advantageous geographic position, it is crossed by freight routes connecting Azerbaijan and the whole of Transcaucasia with the North Caucasus and Central Asia. Highways run from the peninsula to every corner of the republic.

Although it is on the shores of the Caspian Sea, the Abşeron region nevertheless remains one of the most arid parts of Azerbaijan. Its main natural wealth is mineral, including oil, natural gas, iodobromide waters, and limestone used in building and cement production. Baku owes its modern growth to the development of the oil industry; oil derricks encircle the city, and the oil refineries and processing plants attract workers from many areas. Modern Sumqayıt, 22 miles (35 kilometres) northwest of Baku, is currently a centre of the iron and steel, nonferrous metallurgical, and chemical industries, although the development of light engineering is envisaged.

The Quba-Xaçmaz region lies to the north of Abşeron. Its coastal lowlands specialize in grain and vegetable production, while vast orchards surround the towns of Quba and Qusar. The mountain slopes are used for grazing. Special breeds of sheep are raised; their skins are used in the local fur industry.

The Shirvan region, an industrially and agriculturally developed part of Azerbaijan, is centred on the Shirvan Plain. The Mingäçevir hydroelectric station is located there. The area also has a well-developed network of roads. Industry is generally engaged in the processing of such agricultural products as cotton, grapes, and fruit. The most important vineyards lie in the vicinity of Şamaxı, a town famed for its wines, notably Matrasa and Shemakha, which are, respectively, dry red and sweet. In Kürdämir a fragrant dessert wine is produced. The best varieties of pomegranates are grown near Göyçay.

The Mugano-Salyan region, lying south of the Kura River and within the boundaries of the Mili and Mugan plains, specializes in cotton growing (under irrigation), producing about seven-tenths of the gross cotton output of Azerbaijan. Cotton-ginning plants are located in Bärdä, Salyan, and Äli-Bayramlı, all of which, in addition to being on the Kura River, have the advantage of being located on railways and motor roads. A thermal power station stands near Äli-Bayramlı.

The southwestern region includes Nagorno-Karabakh and the Laçin, Füzuli, and Qubadlı administrative districts. Because the average altitude is 4,900 feet, it is one of the areas in the country where broken relief impedes the development of transport, industry, and agriculture. Agricultural production is concentrated in the mountain valleys. Animal husbandry constitutes a large percentage of the gross agricultural output, the leading branches being sheep and pig raising. Grapes, tobacco, and grain are the main crops; wine-making, silk-making, and electrical engineering are the main industries.

The Gäncä-Qazax region is situated in the centre of Transcaucasia near the junction of Azerbaijan, Armenia, and Georgia. The region has conditions favourable both for human life and for intensive agriculture. Trade routes have crossed this part of Azerbaijan from time immemorial, and the ancient town of Ganja (Gäncä) was founded here. It is an industrial centre, with food, engineering, chemical, and nonferrous metallurgical industries. Naftalan is a health resort.

The Şäki-Zaqatala region includes the towns of Şäki, Zaqatala, and Balakän. Its territory borders the Greater Caucasus range, which shelters it from cold northern winds. The numerous mountain rivers provide ample supplies of water, and the region is densely populated. Agricultural products include tobacco, aromatic plants (mint, basil, and roses), rice, corn (maize), and various fruits. The area is also a major producer of hazelnuts and walnuts.

The Naxçıvan region is a typical semidesert, although irrigation has made it possible to cultivate grapes, cotton, and grain. There are several sources of mineral water in the foothill areas.

Azerbaijan has not adopted a new constitution to replace its 1978 Soviet-era constitution, although this document has been revised or superseded by the 1991 Act of Independence and by presidential and parliamentary decree. The head of state is a directly elected president, whose authority was expanded in 1993. The 450-member Supreme Soviet was abolished in 1992 and replaced with a 50-member National Assembly (Milli Majlis). Azerbaijan experienced political instability after independence: its first two elected presidents were deposed, partly as a result of popular protests over Azerbaijan's military failures in Nagorno-Karabakh.

Major political parties include the pro-Turkish, nationalist Azerbaijan Popular Front, the Social Democratic Party, the Communist Party of Azerbaijan (banned in 1991 but relegalized in 1993), the Muslim Democratic Party, and the Azerbaijani Movement for Democratic Reforms.

In 1992 Azerbaijan joined the United Nations, and in 1993 it formally became a member of the Commonwealth of Independent States (CIS).

Azerbaijan formed a national military in 1991, including an army (consisting partly of personnel and matériel from the Soviet 4th Army), navy, and air force. Russian forces completed their withdrawal from Azerbaijan in 1993. Azerbaijan's navy serves under the command of the CIS. A conscription law requires at least 17 months of service from adult males. The conflict with Armenia over Nagorno-Karabakh dominated Azerbaijani military planning during the 1990s.

The Ministry of Internal Affairs, which is responsible for internal security and general police work, was reorganized in 1993. Crime rates in Azerbaijan rose during the 1990s, exacerbated by the social dislocation that accompanied the Nagorno-Karabakh conflict.

Education at all levels is supported by taxes levied upon working people and firms and is available without tuition charge. The country has had obligatory eight-year education since 1959. In the Soviet period illiteracy was virtually eradicated, and a network of institutes of higher education, research centres, and similar bodies was established.

The Azerbaijan State University (founded 1919), located in Baku, has 12 faculties; it offers evening and correspondence courses. The Azerbaijan Polytechnic Institute (founded 1950) is also in Baku. The Azerbaijan Academy of Sciences (founded 1945) coordinates the activities of research centres, including institutes of cybernetics, physics, theoretical problems of chemical technology, petrochemical processes, and genetics.

Azerbaijan has a well-established health service with some specialized clinics and medical research institutes. Medical services, provided free to patients, are supported by general taxation on individual workers and by taxes on income of factories and other firms. Even so, levels of social and cultural benefits are comparatively low.

In the course of its long history, Azerbaijan has given the world a number of outstanding thinkers, poets, and scientists. Among the medieval scientists and philosophers, Abul Hasan Bakhmanyar (11th century), the author of numerous works on mathematics and philosophy, and Abul Hasan Shirvani (11th–12th centuries), the author of Astronomy, may be noted. The poet and philosopher Nẹzāmī, called Ganjavī after his place of birth, Ganja, was the author of Khamseh (“The Quintuplet”), composed of five romantic poems, including “The Treasure of Mysteries,” “Khosrow and Shīrīn,” and “Leyli and Mejnūn.”

The people of Azerbaijan have retained their ancient musical tradition. For example, the art of ashugs, who improvise songs to their own accompaniment on a stringed instrument called a kobuz, remains extremely popular. Mugams, vocal and instrumental compositions, are also widely known, the town of Shusha being particularly renowned for this art.

Azerbaijan's cultural institutions, including museums, theatres, and public libraries, are located in Baku. Many of them were established after World War II. The city has museums devoted to the art, history, and literature of Azerbaijan. In Nagorno-Karabakh there is a museum with material on the history and archaeology of the Armenian people of the region.

The opera and ballet are widely attended. Some of Azerbaijan's composers, notably Uzeir Hajjibekov (the operas Ker-Ogly and Leyli and Mejnūn and the operetta Arshin Mal ʾAlan) and Kara Karayev (the ballets Seven Beauties and The Path of Thunder), have international reputations. The latter's symphonic music is also well known abroad.

Throughout the Soviet period Azerbaijani literature was controlled by a system that saw mortal danger in even a modicum of creative freedom. Azerbaijani writers and other intellectuals were closely supervised and subjected to varying degrees of persecution.

Azerbaijan has no private publishing; several government firms publish scientific books and magazines as well as books and magazines about art and literature in Azerbaijani, Russian, and other languages. In 1992 the Azerbaijani government switched from the Cyrillic to the Roman alphabet.

The magazines Literaturny Azerbaydzhan (in Russian), Azerbaijan Gadïnï (“Azerbaijan Woman,” in Azerbaijani), and Azerbaydzhanskoye neftyanoye khozyaystvo (“Azerbaijan Petroleum Economy,” in Russian) have the highest circulation.

Baku has several radio stations, a television studio, and a film studio.

In ancient and early medieval times, eastern Transcaucasia was populated by Iranian speakers, nomadic Turkic tribes, Kurds, and the Caucasian Albanians, who converted to Christianity in the 4th century and came under the cultural influence of the Armenians. After Arab incursions in the 7th century, Islamic polities were established under local rulers called shāhanshāhs. The Seljuq invasions in the 11th century changed the composition of the local population and resulted in the linguistic dominance of Oghuz Turkic languages. But, unlike the Ottoman Turks who came to dominate Anatolia, the Caucasian Muslims (Islāmic world) of Azerbaijan in the early 16th century became Shīʿite, rather than Sunni, Muslims, and they continued to develop under Persian social and cultural influence. Persian-ruled khanates in Shirvan (Şamaxı), Baku, Ganja (Gäncä), Karabakh, and Yerevan dominated this frontier of Ṣafavid Iran.

After a series of wars between the Russian Empire and Iran, the treaties of Golestān (Gulistan; 1813) and Turkmenchay (Torkmānchāy; 1828) established a new border between the empires. Russia acquired Baku, Shirvan, Ganja, Nakhichevan (Naxçıvan), and Yerevan. Henceforth the Azerbaijani Turks of Caucasia were separated from the majority of their linguistic and religious compatriots, who remained in Iran. Azerbaijanis on both sides of the border remained largely rural, though a small merchant class and working class appeared in the second half of the 19th century. As Baku became the major source of oil for Russia, tens of thousands of Iranian, Armenian, and Russian workers streamed to the Abşeron Peninsula in search of employment, and Russian economic and political influence could be felt in both parts of Azerbaijan. As the source of employment and the home of the nascent Azerbaijani intelligentsia and revolutionary movement, Baku radiated its influence in Iranian Azerbaijan as well as north of the Aras (Araz) River. No specifically Azerbaijani state existed before 1918, and, rather than seeing themselves as part of a continuous national tradition, like the Georgians and Armenians, the Muslims of Transcaucasia saw themselves as part of the larger Muslim world, the ummah. They were referred to as “Tatars” by the Russians; the ethnonym Azerbaijani (azarbayjanli) came into use in the prerevolutionary decades at first among urban nationalist intellectuals. Only in the Soviet period did it become the official and widely accepted name for this people.

Incorporation into the Russian Empire provided a new outlet for educated Azerbaijanis, some of whom turned from their religious upbringing to a more secular outlook. Prominent among the early scholars and publicists who began the study of the Azerbaijani language were ʿAbbās Qolī Āghā Bāqıkhānlı (Bakikhanov), who wrote poetry as well as histories of the region, and Mīrzā Fatḥ ʿAlī Ākhūndzādeh (Akhundov), author of the first Azerbaijani plays. Though eventually these figures would be incorporated into a national narrative as predecessors of the Turkic revival, a variety of conflicting impulses stimulated early Azerbaijani intellectuals—loyalty to the tsarist empire, the continuing influence of Persian culture, and a longing for Western learning. Although no single coherent ideology or movement characterized the Azerbaijani intelligentsia, by 1905 a growing number of writers and journalists adopted the program of the nationalist intellectual ʿAlī Bay Huseynzadeh: “Turkify, Islamicize, Europeanize” (“Turklashtirmak, Islamlashtirmak, Avrupalashtirmak”).

The town of Baku, which by 1901 produced more than half of the world's output of petroleum, was complexly segregated, with Russians and Armenians in the central part of the town and Muslims clustered in distinct districts. As social resentments festered, particularly in times of political uncertainty, ethnic and religious differences defined the battle lines; bloody clashes between Azerbaijanis and local Armenians took place in 1905 and 1918. A hierarchy of skills, education, and wages placed Muslims on the bottom and Christians at the top. By virtue of a quota on non-Christian representation and a system of suffrage based on property holdings, the Baku city duma (legislative council) remained in the hands of wealthy Armenians and Russians. Azerbaijanis remained on the fringe of the labour movement and were indifferent to or ignorant of the aspirations of both their socialist and nationalist intellectuals. None of the small parties and political groups that arose after 1905 commanded much of a following beyond the intelligentsia, though Musavat (“Equality”), founded in 1911 and led by Mehmed Emin Rasulzadeh, proved most enduring. Anxiety about the Armenian “threat,” a perception of their own distance from and hostility to this privileged element within their midst, and a feeling that Azerbaijanis were connected in important ways to other Muslims, particularly Turks, became part of an Azerbaijani sense of self.

With the Bolshevik victory in the Russian Revolution (Russian Revolution of 1917) of 1917 and the withdrawal of Russian troops from the Caucasian front during World War I (1914–18), Azerbaijani leaders joined Armenians and Georgians in a brief experiment in Transcaucasian autonomy (February to April 1918). An even briefer attempt at unity in an independent federative republic of Transcaucasia (April to May) fell apart, and finally three separate independent republics were established. Azerbaijan was declared an independent state on May 28, 1918, but Baku remained in the hands of a communist government, assisted by local Armenian soldiers, who had put down a Muslim revolt in March. Allied with the advancing Turkish army, in September 1918 the Azerbaijani nationalists secured their capital, Baku, and engaged in a massacre of the Armenians.

However, even as they secured control of Baku, the Azerbaijani nationalists were faced with a mixed population of Russian, Armenian, and Muslim workers who had undergone a long socialist and trade-unionist education. Among the peasantry on whom they depended, national consciousness was still largely absent, and the nationalists were never fully secure in Baku, where Bolshevism had deep roots. With the end of World War I, the Turks withdrew; they were replaced by the British, who remained until August 1919. The fragile republic received de facto recognition from the Allies on January 15, 1920, but when the Red Army marched into Baku in April 1920 there was little resistance.

The Azerbaijani Soviet Socialist Republic lasted 71 years. It was part of the Transcaucasian Soviet Federated Socialist Republic from 1922 until 1936 and, like Georgia and Armenia, it experienced considerable economic development, urbanization, and industrialization. Although education in Azerbaijan was promoted and Azerbaijanis were placed in positions of power, the republic was tightly controlled by Moscow, especially during the years of Joseph Stalin's rule (1928–53) when M.A. Bagirov headed the Azerbaijani Communist Party. Becoming a more urban, educated, and socially mobile society, Azerbaijan was divided between more traditional, underdeveloped rural areas and the cosmopolitan city of Baku. After the death of Stalin, the republic enjoyed somewhat greater autonomy, and the national political and intellectual elites flourished.

When conflict with the Armenians of the Nagorno-Karabakh Autonomous Region within Azerbaijan broke out in February 1988, these elites provided the leaders both for the oppositional Azerbaijan Popular Front and for their communist opponents. Violent protests and interethnic clashes targeting both Armenians and Azerbaijanis in the late 1980s, anti-Armenian pogroms in Sumgait in 1988 and in Baku in 1990, as well as continual warfare between the Azerbaijanis and the Armenians of Nagorno-Karabakh, led to military action by Moscow against the republic in January 1990. With the dissolution of the Soviet Union late the following year, the Republic of Nagorno-Karabakh was declared; following a referendum indicating popular support for independence, as well as an election in December, the republic's independence was officially proclaimed in the first days of 1992, a move unrecognized by the international community. The full-scale conflict that exploded between the Armenians in Nagorno-Karabakh and the Azerbaijanis shortly thereafter was finally halted by a 1994 cease-fire, which, though periodically violated, largely managed to hold.

The Communist Party of Azerbaijan retained its power until 1992. After the abortive coup against the Soviet leader Mikhail Gorbachev (Gorbachev, Mikhail) in Moscow in August 1991, Azerbaijan declared itself independent, and the head of the party, Ayaz Mutalibov, was elected its first president. In May 1992 the Azerbaijan Popular Front overthrew Mutalibov and forced new elections, in which its candidate, Abulfez Elchibey, emerged victorious on a platform of separating from the Commonwealth of Independent States and maintaining control over Nagorno-Karabakh. Elchibey was himself overthrown in June 1993 by Heydar Aliyev, a former KGB official and leader of the Azerbaijani Communist Party who had adopted the rhetoric of Azerbaijani nationalism.

Over the next decade, the Aliyev government maintained control—reportedly through intimidation of the press and opposition groups and through manipulation of elections—but was unable to resolve the conflict over Nagorno-Karabakh, despite numerous summit meetings between Aliyev and Armenian leaders. Complicating the discussions was the 1992 declaration of independence that had been issued by the self-proclaimed Republic of Nagorno-Karabakh. The enclave held periodic elections thereafter, the results of which were soundly rejected by Azerbaijan as illegal under international law. In addition, the fighting in Nagorno-Karabakh resulted in the displacement of substantial populations of both Armenians and Azerbaijanis, and, by the time of the 1994 cease-fire, the Nagorno-Karabakh Armenians had expanded their hold over Azerbaijani territory.

At the beginning of the 21st century, roughly one-seventh of Azerbaijan's territory remained outside its control, and significant populations remained displaced, particularly in the case of the Azerbaijanis, many of whom also remained displaced internally. Tensions were further inflamed in the late 1990s by the appointment of a former president of Nagorno-Karabakh to the post of prime minister in Armenia; in Azerbaijan the move was largely viewed as a deliberate provocation, and talks were hampered further. Relations were also strained with Russia, which felt that the government in Azerbaijan was doing little to stop Chechen rebels from operating out of Azerbaijani territory.

In the meantime, oil (petroleum) revenues in Azerbaijan began to soar, as new fields were discovered and new contracts were signed with Western companies for their exploitation. In 2003 the elderly Aliyev died and was succeeded by his son, Ilham, whom Aliyev had been grooming for succession. Scandalized by the apparent accession to power of a hereditary line, opposition political groups staged a series of violent protests that failed to keep the younger Aliyev from the presidency. During the course of his term, Aliyev directed income from the boom in Caspian oil in part toward developing Azerbaijani military capacity, which in 2006 was described as nearing the capability needed to challenge the forces in Nagorno-Karabakh. That same year, Nagorno-Karabakh passed a referendum approving a new constitution, and, in the year that followed, it held its fourth round of elections. Though leadership in the disputed region had hoped that such shows of democratic rule would support the territory's claim to sovereignty, neither Azerbaijan nor the remainder of the international community recognized the region's claims to independence.

Aliyev secured reelection in the presidential vote of October 2008 amid an opposition boycott against the election's restrictive measures. International observers indicated concerns that the proceedings were not sufficiently free and fair, partly because of media restrictions and a lack of robust competition. Early in his second term, Aliyev signed an agreement with Armenian Pres. Serzh Sarkisyan that pledged to intensify the countries' efforts to settle the Nagorno-Karabakh conflict.

geographic region that comprises the extreme northwestern portion of Iran. It is bounded on the north by the Aras River, which separates it from independent Azerbaijan and Armenia; on the east by the Iranian region of Gīlān and the Caspian Sea; on the south by the Iranian regions of Zanjān and Kordestān; and on the west by Iraq and Turkey. Azerbaijan is about 40,000 square miles (100,000 square km) in area.

Iranian Azerbaijan was a centre of several ancient civilizations. It formed part of Urartu and later of Media. In the 4th century BC it was conquered by Alexander the Great and was named Atropatene after one of Alexander's generals, Atropates, who established a small kingdom there. The area returned to Persian (Iranian) rule under the Sāsānians in the 3rd century AD. The Arabs controlled Azerbaijan from the 7th century until Turkish nomads overran it in the 11th century. Thenceforth the inhabitants of the region were Turkish speakers. The region was overrun by the Mongols in the 13th century, and, under the ruler Hülegü, Azerbaijan became the centre of a Mongol empire extending from Syria on the west to the Oxus River (now Amu Darya) on the east. Tabrīz, the region's largest city, was the capital of this empire and became a centre of cultural and commercial life.

Tabrīz was subsequently the capital of the Turkman dynasties of the Kara Koyunlu and Ak Koyunlu (1378–1502). In the early 16th century Azerbaijan was the cradle of the Ṣafavid dynasty, and subsequently the area was fought over by the Ottoman Turks and the Iranians until Nādir Shāh expelled the Turks in the 1740s. During the 18th century the Russians gradually encroached on the area, but the Iranians managed to retain control.

In the early 20th century Azerbaijan was the cradle of the revolutionary movement that gave Iran its constitution in 1906. The area was briefly occupied by the Turks in World War I and was held by the Soviet Union during World War II. In 1945 the Soviets set up the short-lived Kurdish Republic in western Azerbaijan and the communist-dominated Sovereign Republic of Azerbaijan in western Azerbaijan, but Iranian forces regained control of the region in 1946–47 once the Soviet armed forces had withdrawn back across their border.

Iranian Azerbaijan is composed of high plateaus with elevations from 5,000 to 6,000 feet (1,500 to 1,800 m) and lower-lying depressions averaging from 3,000 to 5,000 feet (900 to 1,500 m) in elevation. The eastern part of the Zagros Mountains run north-south through Azerbaijan, and the overall effect is of a stair-step topography, with fault scarps defining a number of basins and lowland depressions. Large volcanic cones, such as Sabalān (15,787 feet 【4,812 m】) and Sahand (12,172 feet 【3,710 m】), dot the high plateau, and the region is subject to earthquakes.

Rainfall is relatively heavy over much of the plateau, and perennial streams have cut gorgelike valleys in places. The average annual precipitation varies from 12 to 35 inches (300 to 900 mm). Azerbaijan is thus one of the few regions in Iran that receives enough rainfall to permit farming without the use of irrigation. The major rivers are the Aras in the north, with its tributary, the Qareh Sū; the Qezel Owzan in the east, with its tributaries, the Qarānqū and Aidughmish; and the Zarrīneh (Jaghātū). The climate is extreme, with hot, dry summers alternating with cold, snowy winters. In western Azerbaijan is Lake Urmia (Urmia, Lake), a shallow, highly saline lake that covers anywhere from 1,750 to 2,300 square miles (4,500 to 6,000 square km), depending on the season.

The population consists mainly of Azeri-speaking Turks who use an Arabic script and are Shīʿite Muslims. There are also some Kurds and Armenians. The Kurds are Sunnites, and the Armenians are Christians. Agriculture is the principal occupation of the people. The most fertile agricultural lands are around Lake Urmia. Crops include barley, wheat, rice, indigo plants, potatoes, sugar beets, walnuts, almonds, fruits, and vegetables. Sheep and goats are also raised. Industries, concentrated mainly in Tabrīz, produce tractors, factory machinery, cement, textiles, electrical equipment and tools, animal fodder, turbines, motorcycles, clocks and watches, processed foods, and agricultural implements. Elsewhere in the region are sugar mills, textile mills, and food-processing plants. Coarse carpets and rugs are woven, and metalware is produced on a small scale. Copper, arsenic, kaolin, coal, salt, lead, and building stone are mined. A network of roads links the region's main cities, including Tabrīz, Orūmīyeh, Ardabīl, Mahābād, and Marāgheh, with each other, and an oil pipeline runs from Tabrīz to Tehrān.