The new biography of Konstantin Eduardovich Tsiolkovsky (1857-1935), written by Doctor of Philosophy V.N. Demin, is radically different from all previous ones. The founder of domestic and world cosmonautics is presented here not only as a brilliant scientist and inventor, but also as an outstanding cosmist philosopher who determined the ideological and methodological vector of the development of science and philosophy for many decades to come. This is the story of the spirit, quests, doubts, stunning ups and tragic disappointments of a man who became the personification of science of the 20th century.