The book is dedicated to the history of the Khazars - a mysterious nomadic people whose power was enormous, the territory was located between the lower reaches of the Volga and the northern slopes of the Caucasus, stretching to the Sea of Azov, and in the 9th century even further to the west - to Kyiv and the middle reaches of the Dnieper, and who later disappeared without a trace. The origins of the Khazars, their possible connections with the Persians before Islam, contacts at different times between the Khazars and the Greeks, wars with the Arabs, the conversion of the Khazars to Judaism, connections between the Khazars and the Rus and, finally, the collapse and disappearance of the Khazar state are considered. It is told about the search for traces of the Khazars far to the west - in Denmark and to the east - in China, and also about the fact that in addition to Judaism - this is an established fact - the Khazars also probably accepted Buddhism and Christianity at different times.