Description:This book presents a unified theoretical and conceptual framework for the description of various irreversible phenomena in quantum mechanics. The general theory of irreversible processes is applied to specific physical models and situations such as energy and electron transfer processes, tunnelling in condensed media, superradiance, etc. Special attention is given to memory effects in relaxation processes and dissipationless states in dissipative systems. A separate chapter is devoted to the problem of irreversibility in quantum measurements. Audience: This book will be of interest to postgraduate students and specialists in quantum mechanics, statistical physics, and chemical physics. The work may serve as a complementary text for quantum mechanics courses.