Leading researchers and experts present wide-ranging methods for detecting and isolating expressed gene products-recombinant proteins. These state-of-the-art techniques describe a large number of molecular tags and labels, including enzymes, ligand-binding moieties, and immunodetectable molecules. There are also methods to detect interactive proteins and gene expression-mediated alterations in cellular activity, as well as chapters on in situ detection of gene expression. When combined with a companion volume by the same editor, Recombinant Gene Expression Protocols, both volumes guide the research worker through the entire journey of recombinant gene expression.