An internationally known scientist proposes a scenario that succeeds in explaining why, in the great extinction 65 million years ago, certain groups of animals such as the dinosaurs were extinguished while others survived. He also offers a new model of the origin of the solar system that for the first time provides a coherent account of the formation and placing of the planets, and estimates the average time between mass extinctions. Written in a lively and accessible manner, this book offers abundant new material and it will serve as an indispensable reference.