This book describes the basic facts, concepts and ideas of polymer physics in simple, yet scientifically accurate, terms. In both scientific and historic contexts, the book shows how the subject of polymers is fascinating, as it is behind most of the wonders of living cell machinery as well as most of the new developments in materials. No mathematics is used in the book beyond modest high school algebra, yet very sophisticated concepts are introduced and explained, ranging from scaling and reptations to protein folding and evolution. This new edition includes an extended section on polymer preparation methods, discusses knots formed by molecular filaments, and presents new and updated materials on polymer properties of proteins and their roles in biological evolution.