München und Berlin: Druck und Verlag von R. Oldenbourg, 1923. Octavo, pp. [1-4] 5 [6-7] 8 [9] 10-92, three folded plates (one counted as figure 53), other figures in the text, original decorated gray wrappers printed in black, all edges untrimmed. First edition. The first technical book on space travel. "... Oberth's book became the sole cornerstone of all later space-travel ideas ..." - Ley, Rockets, Missiles, and Space Travel (1951), p. 109. [Reference: Ciancone 176. Hübner 694. Interlibrum 270 #260. Ley, Rockets, Missiles, and Space Travel, revised edition, 1957, p. 507].