This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show ihe link between experiments and theory. The intention is not to present a compilation ol the currently available literature on the subject. Very few reference actions have thus been made. Each chapter has essentially the same slruclure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 300-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1—12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing direclly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in the first chapter. The next eight chapters deal with different phenomena (processes) and states of polymers. Ihe last three chapters were written with the intention of making the reader think practically about polymer physics. How can a certain type of problem be solved? What kinds of experiment should be conducted?