This completely rewritten new edition begins with a historical perspective of the place of the solar system in the universe. Evidence from meteorites is used to describe how the planets were formed and the giant planets are considered in the light of the discovery of new extrasolar giants. Other chapters discuss satellites, comets, centaurs, asteroids and why Pluto is not a planet. Explanations on why Earth and Venus turned out so differently, and how Mars and Mercury are the survivors of many similar bodies, are also discussed.