Arthur Koestler found an original answer to the ideology of anti-Semitism. In his opinion, the fall of the Khazar Kaganate gave rise to several waves of migration that formed the main core of the population professing Judaism in Eastern Europe. Since the ethnic migrants from Khazaria were not Semites, anti-Semitism is also untenable. Drawing on the texts of Arab travelers of the 9th-10th centuries, Byzantine sources, The Tale of Bygone Years, the works of Artamonov, Kokovtsov, Toynbee, Vernadsky, Dunlop, Kuchera, Polyak and many other historians, the author offers a slightly different vision of the formation and collapse of the Khazar state . The seemingly paradoxical choice of faith takes on different accents. A fascinating study of the history of the Khazar Kaganate, which throughout its existence was under the cross-pressure of multidirectional state, religious and political interests will not leave the reader indifferent, for the History behind the pages of Koestler’s book does not tolerate indifference. The Eurasia publishing house is grateful to the Hutchinson & Co publishing house (Publishers) Ltd. for reporting that the rights to this work by Arthur Koestler are considered public domain.