As more genetic and biochemical information about the protein components of cells accumulate, the analysis of protein-protein interactions is becoming increasingly important. This manual presents a wide range of techniques for identifying and analyzing these interactions, starting with standard molecular and biochemical techniques, and progressing to biophysical and computational approaches and therapeutic and other post-genomic applications. This manual is designed to complement the information in the best-selling Molecular Cloning manual, and is presented in the same clear, user-friendly format. It is an essential resource for investigators studying interacting sets of proteins and their physiologic significance in a wide range of experimental systems.