The second, revised and expanded, edition of the textbook (the previous one was published in 2000) is devoted to one of the most important sections of general psychology - the theory and methodology of the study of volitional processes. The book, from the author’s perspective, analyzes traditional and the latest scientific, philosophical, psychological and physiological ideas about the phenomena of the volitional sphere of man (in particular, about “willpower”), traces the patterns of its development in ontogenesis, as well as its manifestations in various types of behavior and activities , issues of the pathology of will are considered. In a systematic form, the manual presents little-known psychodiagnostic methods for studying will, which can be successfully used in the practical activities of specialists in the education system, sports and production-organizational spheres. The publication is addressed to psychologists, psychophysiologists, teachers, as well as university students faculties of psychological and pedagogical profiles.