The third in the six-volume Sky and Telescope Library of Astronomy draws from that magazine for articles on the origin of the solar system. Ranging from 1931 to 1964 in date of publication, they are written by leading astroseers (Struve, Shapley, Urey, etc.). They are mostly speculative, centering around the origin of the earth and planets and the riddles of life in other worlds. There is a bewildering variety of theories, and doubtless the present nebular hypotheses will seem as naive in ten years as the star-bumping ideas of 1930 seem to day. Nevertheless, the topic seems more suitable to the historical, evolutionary presentation offered than the subject taken up in Neighbors of the Earth (p. 561, 1965); the volume is consequently less dated. It provides ideas to intrigue readers who have done some homework in elementary astronomy.