Immanuel Velikovsky (; ; 17 November 1979) was a Russian and American psychoanalyst, writer, and catastrophist. He is the author of several books offering pseudohistorical interpretations of ancient history, including the U.S. bestseller Worlds in Collision published in 1950. (quoted on website of Ruth Velikovsky Sharon) Velikovsky's work is frequently cited as a canonical example of pseudoscience and has been used as an example of the demarcation problem.

His books use comparative mythology and ancient literary sources (including the Old Testament) to argue that Earth suffered catastrophic close contacts with other planets (principally Venus and Mars) in ancient history. In positioning Velikovsky among catastrophists including Hans Bellamy, Ignatius Donnelly, and , 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."Clube, S. V. M. and Bill Napier 1984. Velikovskians In Collision. Quadrant (Sydney). Jan.–Feb., pp. 33–34; reprinted in Kronos vol. IX, no. 3, 1984. pp. 44–49. 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 (–750 BC) and reconciling biblical accounts with widely accepted archaeology and Egyptian chronology.

In general, Velikovsky's ideas have been ignored or vigorously rejected by the academic community.Trevor Palmer, Perilous Planet Earth: Catastrophes and Catastrophism through the Ages, Cambridge University Press, . pp. 116–19. Nonetheless, his books often sold well and gained enthusiastic support in lay circles, often fuelled by claims of unfair treatment of Velikovsky by orthodox academia.Cohen, Daniel (1967). Myths of the Space Age, Dodd Mead. LCCN 67-25108. Chap. VIII, Immanuel Velikovsky – the Man Who Challenged the World, pp. 172–94.Gordon, Theodore J. (1966). Ideas in Conflict, St. Martin's Press. LCCN 66-23261. Chap. 2, The Miracles of Exodus, pp. 18–48.Fair, Charles (1974). The New Nonsense: The End of the Rational Consensus, Simon and Schuster. . Chap. viii, Speaking of Flying Objects ..., pp. 139–86. The controversy surrounding his work and its reception is often referred to as "the Velikovsky affair".Bauer, Henry H. (1992). The Velikovsky Affair Aeon, 2 (6), 75–84. Homestead.com This article, a comprehensive overview, originally appeared in Dec. 1988 La Recherche, pp. 1448–55.Bauer, Henry H. (1996). Velikovsky, Immanuel, in Gordon Stein (editor), The Encyclopedia of the Paranormal. Prometheus Books. . pp. 781–88.Grove, J. W. (1989). In Defence of Science: Science, technology, and politics in modern society, University of Toronto Press. . Chap. 5, Pseudo-science, pp. 120–50; adapted from Grove, J. W. (1985). "Rationality at Risk: Science against Pseudoscience". Minerva, 23 (2), 216–40.

Childhood and early education Immanuel Velikovsky was born in 1895 to a prosperous Jewish family in Vitebsk, Russian Empire (now in Belarus). The son of Shimon (Simon Yehiel) Velikovsky (1859–1937) and Beila Grodensky, he learned several languages as a child and was sent away to study at the Medvednikov Gymnasium in Moscow, where he performed well in Russian language and mathematics. He graduated with a gold medal in 1913. Velikovsky then traveled in Europe and visited Palestine before briefly studying medicine at Montpellier in France and taking premedical courses at the University of Edinburgh. He returned to Russia before the outbreak of World War I, enrolled in the University of Moscow, and received a medical degree in 1921.

Editorial work and marriage Upon taking his medical degree, Velikovsky left Russia for Berlin. With the financial support of his father, Velikovsky edited and published two volumes of scientific papers translated into Hebrew. The volumes were titled Scripta Universitatis Atque Bibliothecae Hierosolymitanarum ("Writings of the Jerusalem University & Library"). He enlisted Albert Einstein to prepare the volume dealing with mathematics and physics.

In 1923, Velikovsky married Elisheva Kramer, a violinist and later sculptor.

Career as a psychiatrist Velikovsky lived in what was then the British Mandate of Palestine from 1924 to 1939, practising medicine in the fields of general practice, psychiatry, and psychoanalysis, which he had studied under Sigmund Freud's pupil Wilhelm Stekel in Vienna. During this time, he had about a dozen papers published in medical and psychoanalytic journals. He was also published in Freud's Imago, including a precocious analysis of Freud's own dreams.Velikovsky, I. "The Dreams Freud Dreamed" Psychoanalytic Review Vol. 28 pp. 487–511 (October, 1941), Varchive.org

Emigration to the US and a career as an author In 1939, with the prospect of war looming, Velikovsky travelled with his family to New York City, intending to spend a sabbatical year researching for his book Oedipus and Akhenaton. The book was inspired by Freud's Moses and Monotheism and explored the possibility that Pharaoh Akhenaton was the legendary Oedipus. Freud had argued that Akhenaton, the supposedly monotheistic Egyptian pharaoh, was the source of the religious principles that Moses taught to the people of Israel in the desert. Freud's claim (and that of others before him) was based in part on the resemblance of Psalm 104 in the Bible to the Great Hymn to the Aten, an Egyptian hymn discovered on the wall of the tomb of Akhenaten's courtier, Ay, in Akhenaten's city of Akhetaten. To disprove Freud's claim and to prove the Exodus as such, Velikovsky sought evidence for the Exodus in Egyptian documents. One such document was the Ipuwer Papyrus, which he felt reported events similar to several of the Biblical plagues. Since conventional Egyptology dated the Ipuwer Papyrus much earlier than either the Biblical date for the Exodus (–1450 BCE) or the Exodus date accepted by many of those who accepted the conventional chronology of Egypt (), Velikovsky had to revise the conventional chronology.

Within weeks of his arrival in the United States, World War II began. Launching on a tangent from his original book project, Velikovsky began to develop the radical catastrophist cosmology and revised chronology for which he would become notorious. For the remainder of the Second World War, now as a permanent resident of New York City, he continued to research and write about his ideas, searching for a means to disseminate them to academia and the public. He privately published two small Scripta Academica pamphlets in 1945 (Theses for the Reconstruction of Ancient History and Cosmos Without Gravitation). He mailed copies of the latter to academic libraries and scientists, including Harvard astronomer Harlow Shapley in 1947.

In 1950, after eight publishing houses rejected the Worlds in Collision manuscript,Velikovsky, Immanuel (1983). Stargazers and Gravediggers, William Morrow & Co. . p. 63. it was finally published by Macmillan, which had a large presence in the academic textbook market. Even before its appearance, the book was enveloped by furious controversy, when Harper's Magazine published a highly positive feature on it, as did Reader's Digest, with what would today be called a creationist slant. This came to the attention of Shapley, who opposed the publication of the work, having been made familiar with Velikovsky's claims through the pamphlet Velikovsky had given him. Shapley threatened to organise a textbook boycott of Macmillan for its publication of Worlds in Collision, and within two months the book was transferred to Doubleday. It was by then a bestseller in the United States. In 1952, Doubleday published the first installment in Velikovsky's revised chronology, Ages in Chaos, followed by the Earth in Upheaval (a geological volume) in 1955. In November 1952, Velikovsky moved from Manhattan to Princeton, New Jersey.

For most of the 1950s and early 1960s, Velikovsky was persona non grata on college and university campuses. After this period, he began to receive more requests to speak. He lectured, frequently to record crowds, at universities across North America. In 1972, the Canadian Broadcasting Corporation aired a one-hour television special featuring Velikovsky and his work, and this was followed by a thirty-minute documentary by the BBC in 1973.

During the remainder of the 1970s, Velikovsky devoted a great deal of his time and energy to rebutting his critics in academia, and he continued to tour North America and Europe to deliver lectures on his ideas. By that time, the elderly Velikovsky had diabetes and intermittent depression, which his daughter said may have been exacerbated by the scientific community's continuing rejection of his work.Sharon, Ruth Velikovsky: Aba: The Glory and the Torment. The Life of Dr. Immanuel Velikovsky McGraw Hill, 1995 He died in 1979.

Posthumous administration of literary estate For many years, Velikovsky's estate was controlled by his two daughters, Shulamit Velikovsky Kogan (b. 1925), and Ruth Ruhama Velikovsky Sharon (b. 1926),Duane Vorhees, "The Early Years: Part Two", Aeon III:1 (Nov 1992). See also the Web site of Ruth Velikovsky Sharon who generally resisted the publication of any further material. (Exceptions include the biography ABA – the Glory and the Torment: The Life of Dr. Immanuel Velikovsky, issued in 1995 and greeted with rather dubious reviews;Vorhees, Duane (1996). Aeon, 4 (2), 107-11.Ellenberger, Leroy (1996). Journal of Scientific Exploration, 10 (4), 561–69., UGA.eduMoore, Brian (1997). Chronology & Catastrophism Review 1997 (2), 51. and a Hebrew translation of another Ages in Chaos volume, The Dark Age of Greece, which was published in Israel.) A volume of Velikovsky's discussions and correspondence with Albert Einstein appeared in Hebrew in Israel, translated and edited by his daughter Shulamit Velikovsky Kogan. In the late 1990s, a large portion of Velikovsky's unpublished book manuscripts, essays and correspondence became available at the Velikovsky Archive website.The Immanuel Velikovsky Archive In 2005, Velikovsky's daughter Ruth Sharon presented his entire archive to Princeton University Library.

Ideas In the 1920s and 1930s, Velikovsky published his concepts in medical and psychoanalytic journals.See Varchive.org for a list He is best known, however, for research performed in the 1940s when living in New York City. His main ideas in this area were summarized in an affidavit of November 1942,Velikovsky, Immanuel (1942). Affidavit, November 23. and two privately published Scripta Academica pamphlets, Theses for the Reconstruction of Ancient History (1945) and Cosmos without Gravitation (1946).Collected at Varchive.com