Immunoassays is the first practical volume designed to help any biologist develop an immunoassay of any common format for any suitable analyte. The basic principles are described and the choices of assay types and formats listed. Methods for raising and for characterizing antibodies, forpreparing radioactive, enzymatic, fluorescent and other labels, are described. Solid-phase reagents, standards and immunogens are explained, with procedures for their preparation. But most components can be obtained commercially and comprehensive lists of suppliers are given. Approaches tocombining the reagents and optimizing the required assay are described, including how to eliminate common interferences, and thorough validation procedures are given. Manual and computer methods for the calculation of concentrations are explained. Since only assays that are within control givevalid results, a graded and comprehensive approach to internal and external quality assurance methods is detailed, including how to prepare control samples.