Once men had grasped the disconcerting but fruitful idea that the earth revolved around the sun, the way was open to a detailed and increasingly precise understanding of the immense yet delicate clockwork of the solar system. This book, written in nontechnical language by a distinguished professor of astronomy, tells how a variety of notable discoveries about the earth and its neighbors were made--describing the men, the observational equipment, and the scientific circumstances involved in each case. Astronomy is now reaching out beyond the solar system, studying stars, their internal processes, and interstellar matter. But these stories of important findings in celestial mechanics have a lasting interest, illustrating the kinds of problems, scientific strategies, and fascinating personalities that have contributed to our knowledge of the skies. They will interest the amateur astronomer, the layman interested in science, and the historian of science. --Back cover.