Since its discovery in I960, the hybridization of somatic cells has evolved from a biological curiosity into an analytical method that today underlies nearly all investigations of the genetic aspects of various biological phenomena. As an eyewitness to this development from its inception forward, Boris Ephrussi here relates the history of somatic hybridization and the formation of its methodology, lie follows with a discussion of the characteristics and properties of the resultant hybrid cells. Together, these topics comprise an authoritative introduction to the principles of the technique. Dr. Ephrussi proceeds to an examination in greater detail of three specific areas of biological research to which the techniques of hybridization are currently being applied with promising consequences. Thus the major part of the book deals with applications of somatic hybridization to mammalian genetics, cell differentiation, and cancer. Originally published in 1972. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.