Lev Nikolaevich Gumilev (1912–1992) - an outstanding historian and ethnologist. The son of famous parents - A. Akhmatova and N. Gumilev - he was forced to resist the blows of fate all his life and, despite all misfortunes, managed to reach unprecedented heights in science. The books “Ethnogenesis and the Earth’s Biosphere” and “In Search of a Fictitious Kingdom,” included in this publication, are two of the scientist’s most famous works. The first of them substantiates the theory of passionarity and traces the patterns of interaction between ethnic groups and landscapes in history. The second is dedicated to the legend of a Christian state that existed in Central Asia, headed by a king-priest.