The Space Age, with lunar missions and interplanetary probes, has revolutionized our understanding of the Solar System. Planets and large moons have become familiar worlds, with a diverse range of properties. Large numbers of asteroids, comets and small moons have now been discovered, and many of these objects studied in detail. As a result, our understanding of the process of star and planet formation is increasing all the time. Planetary Sciences presents a comprehensive coverage of this fascinating and expanding field at a level appropriate for graduate students and researchers in the physical sciences. The book explains the wide variety of physical, chemical and geological processes that govern the motions and properties of planets. Observations of the planets, moons, asteroids, comets and planetary rings in our Solar System, as well as extrasolar planets, are described, and the process of planetary formation is discussed.