Book excerpt: An Introduction to Dynamic Light Scattering by Macromolecules provides an introduction to the basic concepts of dynamic light scattering (DLS), with an emphasis on the interpretation of DLS data. It presents the appropriate equations used to interpret DLS data. The material is presented in order of increasing complexity of the systems under examination, ranging from dilute solutions of noninteracting particles to concentrated multicomponent solutions of strongly interacting particles and gels. Problems are presented at the end of each chapter to emphasize these concepts. Since a major emphasis of this textbook is the interpretation of DLS data obtained by polarized light scattering studies on macromolecular solutions, the results of complementary experimental techniques are also presented in order to gain insight into the dynamics of these systems. This textbook is intended for (1) advanced undergraduate students and graduate students in the chemical, physical, and biological sciences; (2) scientists who might wish to apply DLS methods to systems of interest to them but who have no formal training in the field of DLS; and (3) those who are simply curious as to the type of information that might be obtained from DLS techniques.