The book is divided into four parts: the first part introduces the basic concepts of nicotinamide coenzymes, the synthesis of nicotinamide coenzymes, intracellular distribution, and an overview of the main functions and detection methods so that readers can quickly understand the general feature and function of nicotinamide coenzymes; the second part describes the involvement of nicotinamide coenzymes in intracellular signal transduction and their roles in cellular physiological and biochemical processes to explain exactly how nicotinamide coenzymes work in the processes and enable readers to deeply understand the principle of nicotinamide coenzymes playing an important function; the third part describes the role of nicotinamide coenzymes in the pathophysiological process of diseases, tries to illustrate the specific mechanisms of their association with the occurrence of the diseases, and points out the potential value in future translational medicine research; the fourth part introduces the production technology of nicotinamide coenzymes, including precursors, the process of industrial production, and the application of nicotinamide coenzymes and precursors in health industry, medicine, and life science research. This book can be used as a reference book or textbook for undergraduate and graduate students of life sciences, basic and clinical medicine, researchers, and clinicians.