This book presents a lucid account of physical and mathematical approaches to the fundamental problems of evolutionary biology. The first part treats the interrelations of physics and biology, criticizing in particular the so-called anti-reductionist school. Ideas such as gradualism and punctualism in evolution are described and analysed. The second part is devoted to the molecular foundations of evolution: structure and dynamics of proteins, molecular drive, noncoding DNA. Finally, the problems of evolutionary biology are treated on the basis of synergetics and information theory. In the 1930s Darwin's theory of evolution was united with population genetics. The present book is the first attempt to unify this longstanding framework with our modern knowledge of molecular biology.