A new biography of Konstantin Eduardovich Tsiolkovsky (1857–1935), written by Doctor of Philosophy V. N. Demin, differs radically from all previous ones. The founder of Russian and world cosmonautics is presented here not only as a brilliant scientist and inventor, but also as an outstanding cosmic philosopher who determined the worldview and methodological vector of the development of science and philosophy for many decades to come. This is a story of spirit, quest, doubt, staggering ascents, and tragic disappointments of a man who became the embodiment of twentieth-century science.