Few technical manuals have become standards in biomedicine. Antibodies: A Laboratory Manual, by Ed Harlow and David Lane, has had that status for a decade. Now there is a new and even higher standard-Using Antibodies: A Laboratory Manual. Harlow and Lane have completely revised their guide to the use of immunoglobulin reagents in the laboratory. Chapters have been entirely rewritten, reorganized, and updated to provide background, context, and step-by-step instructions for techniques that range from choosing the right antibody and handling it correctly, to the proper methods for characterizing antigens in cells and solutions. New chapters on tagging proteins and epitope mapping are included. Rather than presenting an array of solutions for working with antibodies and antigens, Using Antibodies instead identifies in each case the best approach to specific problems. These recommendations include more detail in the protocols, extensive advice on avoiding and solving problems, information regarding proper controls, and extensive illustration of theory, methods, and results, both good and bad. An additional bonus included with this manual is a set of Portable Protocols, step-by-step instructions for the most frequently used and essential techniques printed on spill-proof, durable cards that can be annotated and used directly at the bench. The expert advice in Using Antibodies is presented using an imaginative design with extensive use of color and graphic elements calculated to help readers plan and execute their experiments efficiently and accurately. A newly available type of binding will maintain the manual's integrity during years of use. This new manual reflects a decade's additional research experience by two outstanding scientists of international reputation. Since writing the previous manual, Ed Harlow has received many awards, notably the General Motors and Bristol Myers prizes for cancer research, and he was elected to the National Academy of Sciences. David Lane, also the winner of many awards, such as the Yvette Mayent Prize and the Paul Ehrlich and Ludwig Darmstaedter Award, was elected as a Fellow of the Royal Society. The over-the-shoulder advice these experts provide in Using Antibodies will lead all laboratory investigators to success in using these techniques, regardless of experience. Using Antibodies is a required resource for every laboratory in which genes, cells, and proteins are studied.