Konstantin Tsiolkovsky was a Russian and Soviet rocket scientist and pioneer of the astronautic theory. His works later inspired leading Soviet rocket engineers and contributed to the success of the Soviet space program. Tsiolkovsky spent most of his life in a log house on the outskirts of Kaluga, about 200 km southwest of Moscow. A recluse by nature, he appeared strange and bizarre to his fellow townsfolk. This volume contains both his scientific and philosophical works.