This volume on glutathione transferases and gamma-glutamyl transpeptidases serves to bring together current methods and concepts in an interesting, important and rapidly developing field of cell and systems biology. It focuses on particular aspects of the so-called Phase II of drug detoxication, which has important ramifications for endogenous metabolism and nutrition. This volume of "Methods in Enzymology" presents current knowledge and in this field of research. Together with the volumes on "Quinones" and "Quinone Enzymes" (volumes 378 and 382), and on Phase II "Conjugation Enzymes and Transport Systems" (volume 400), the state of knowledge on proteomics and metabolomics of many pathways of (waste) product elimination, enzyme protein induction and gene regulation and feedback control is provided. We trust that this volume will help stimulate future investigations and speed the advance of knowledge in systems biology. It is a laboratory standard for more than 40 years. It is over 400 volumes strong. It is also available on ScienceDirect.