Colombian poet and novelist whose best work, María (1867; Maria: A South American Romance, 1977), was one of the most famous Latin-American novels of the 19th century.

The son of a prosperous English Jew, Isaacs received an excellent education. During the War of the Cauca (1860–63) he was reduced to poverty by the destruction of his estates. Settling in Bogotá in 1864, he published a slight volume of Poesías, which attracted considerable attention and, in 1867, the romantic novel María, which won immediate recognition and remains his best known work. An idyllic picture, very likely autobiographical, of life in his native Cauca Valley, María was translated into several languages. Thereafter, he combined a career in public life with his career in literature.

Although Isaacs continued to write until his death, none of his later efforts fulfilled the promise of his first two volumes.