As in past editions, the basic philosophy of this extremely popular text is to present the principles and techniques of gene manipulation in sufficient detail to enable the non-specialist to understand them. However, in the three years since the previous edition, molecular biology has seen a dramatic increase in available techniques and applications. Every chapter in this new edition has been extensively revised or rewritten to take these developments into account - including a vastly expanded section on the polymerase chain reaction and its manifold applications, a new chapter examining the impact of recombinant DNA techniques on our understanding of human genetics, and extended coverage of gene transfer techniques.