This text is devoted to the characterization of recombinant DNA-derived proteins by peptide mapping. It describes new technological procedures including capillary electrophoresis, analysis of glycopeptides and the use of electrospray and matrix-assisted laser desorption mass spectrometry. The book presents practical procedures for preparing a protein sample, the enzyme digestion, choice of separation method and procedures for the structural analysis of the separated species. Many figures of peptide maps illustrate typical results. Tables of summary information about digestion, separation conditions, and analyses of important protein samples are also presented.