Cellular Energy Metabolism and Its Regulation examines the metabolic and molecular aspects of living organisms. Beginning with a discussion of evolutionary design and its close analogy with human design, it emphasizes the notion that evolution is a process of functional design, and that the characteristics of an organism, whether morphological or molecular, were selected because of functional advantage to the organism’s ancestors. Thus, the study of an enzyme, a reaction, or a sequence can be biologically relevant only if its position in the hierarchy of function is kept in mind. This book deals with some aspects of metabolism from that point of view. The key concepts discussed include the conservation of solvent capacity and energy; functional stoichiometric coupling and metabolic prices; adenylate control and the adenylate energy charge; aspects of enzyme behavior that appear to be related to metabolic control; interactions between metabolic sequences; and the adenylate energy charge in intact cells. This book was designed for graduate students in biochemistry, physiology, microbiology, and related fields. However, it may also be useful to senior undergraduate students and more advanced workers who have a direct or peripheral interest in energy metabolism. It assumes a general familiarity with the material covered in a standard biochemistry textbook as well as some knowledge of such related areas as genetics.