Carrying on the high standards of the much-acclaimed first edition, highly experienced investigators have extensively updated the first edition with many of the new approaches that have been transforming the field. Included in this new edition are readily reproducible immunoassays, fluorescence-based assays, high-throughput methods, protein modification assays, lipid second messenger assays, and chromatin immunoprecipitation techniques. Wherever possible, protocols for the assay of general classes of signal transduction components have been identified so they can be adapted to the assay of any member of that class.