Swiss archaeologist and prehistorian who conducted the first systematic excavation of prehistoric Alpine Lake Dwellings, at Obermeilen on Lake Zürich. He thus initiated the study of similar remains elsewhere in Switzerland and Europe, from which much was learned about Late Stone Age and Bronze Age life.

After becoming a professor of English in Zürich (1831), Keller tried excavating prehistoric burial mounds. In 1832, with other amateur enthusiasts, he founded the Zürich Antiquarian Society and over the next 15 years became absorbed in the young science of European prehistoric archaeology. Excavating widely around Zürich, he gathered a sizable collection of flints, bronzes, and pottery and published papers that earned him an honorary doctorate in archaeology and a reputation as one of Switzerland's foremost archaeologists.

In 1854, at Obermeilen, farmers dredging a broad expanse of mud, in which many wooden pilings were submerged, found flints, bones, and bronze jewelry. They were brought to Keller, who immediately organized a party to examine the site. The results were extraordinary. In addition to more enduring artifacts, pieces of basketry, cloth, and netting were found. Bones included those of domestic animals. Keller theorized that Stone Age or Bronze Age villages had been built on the pilings submerged in the lake bed. Publication of his first findings created a sensation, and the rush was on to find other sites to excavate. His papers appeared in English as The Lake Dwellings of Switzerland and Other Parts of Europe (1866). Other excavators submitted their reports to him, and he devoted much of his time to theorizing on the subject of lake dwellings. At the time of publication of his eighth report (1879), 161 sites had been authenticated in Switzerland, and work was under way on sites in Austria, France, and Italy.