Hermann Oberth (1894-1989), German rocket pioneer, holding his book on rocketry. Oberth presented the earliest mathematical analyses of the theoretical and practical aspects of human travel in space. In 1922, Oberth's doctoral dissertation was rejected. He had it privately published in 1923 as Die Rakete zu den Planetenraumen (By Rocket into Planetary Space), the book seen here. It was later expanded as Ways to travel in Space (1929). Many of Oberth's inventions and suggestions were used in the design of the first rockets launched by the USA and the USSR.