The book is concerned with the application of physical techniques to the study of the structure and interactions of biopolymers. The treatment is confined to those procedures applicable to solutions. The material has been tested on students in actual classes, thereby permitting the elimination of ambiguities and potential points of difficulty. Stress has been placed upon lucidity of treatment, and difficult steps in derivations have been explained. The mathematical exposition has been made as clear and simple as feasible. Examples of actual data are given.