Immanuel Velikovsky (1895 – 1979) was a Russian-born American independent scholar of Jewish origins, best known as the author of a number of controversial books reinterpreting the events of ancient history, in particular the US bestseller Worlds in Collision, published in 1950. Earlier, he played a role in the founding of the Hebrew University of Jerusalem in Israel, and was a respected psychiatrist and psychoanalyst.
His books use comparative mythology and ancient literary sources (including the Bible) to argue that Earth has suffered catastrophic close-contacts with other planets (principally Venus and Mars) in ancient times. In positioning Velikovsky among catastrophists including Hans Bellamy, Ignatius Donnelly, and Johann Gottlieb Radlof, the British astronomers Victor Clube and Bill Napier noted ". . . Velikovsky is not so much the first of the new catastrophists . . . ; he is the last in a line of traditional catastrophists going back to mediaeval times and probably earlier." Velikovsky argued that electromagnetic effects play an important role in celestial mechanics. He also proposed a revised chronology for ancient Egypt, Greece, Israel and other cultures of the ancient Near East. The revised chronology aimed at explaining the so-called "dark age" of the eastern Mediterranean (ca. 1100 – 750 BCE) and reconciling biblical history with mainstream archaeology and Egyptian chronology.
In general, Velikovsky's theories have been ignored or vigorously rejected by the academic community. Nonetheless, his books often sold well and gained an enthusiastic support in lay circles, often fuelled by claims of unfair treatment for Velikovsky by orthodox academia. The controversy surrounding his work and its reception is often referred to as "the Velikovsky affair".