Written in the immediate aftermath of the Sputnik I launch (4 October 1957), this encyclopedic survey covers the state of astronautics at the dawn of the space age. In eleven chapters, Hilaire Cuny addresses cosmology, rocket physics, gravity and special relativity, a complete tour of the solar system, the medical challenges of human spaceflight, cosmic radiation and meteorite hazards, and the social and philosophical implications of space exploration. A complementary bibliography of approximately fifty titles is appended.