This represents the third volume in a series on cancer markers pub­ lished by the Humana Press. The first volume, published in 1980, stressed the relationship of development and cancer as reflected in the production of markers by cancer that are also produced by normal cells during fetal development. The concept that cancer represents a problem of differentiation was introduced by Barry Pierce in describing differenti­ ation of teratocarcinomas. Highlighted were lymphocyte markers, alphafetoprotein, carcinoembryonic antigen, ectopic hormones, enzymes and isozymes, pregnancy proteins, and fibronectin. The second volume, published in 1982 and coedited with Britta Wahren, focused on the diagnostic use of oncological markers in human cancers, which were systematically treated on an organ by organ basis. At that time, the application of monoclonal antibodies to the identification of cancer markers was still in a very preliminary stage. A general introduc­ tion to monoclonal antibodies to human tumor antigens was given there by William Raschke, and other authors included coverage of those mark­ ers then detectable by monoclonal antibodies in their chapters.