Basic trends in experimental and theoretical studies of the problem of will in Western psychology since classical works by N. Ach and till the beginning of the 80-ies are presented in some detail. Conceptualization of the problem of will in the "experimental psychology of will", in K. Lewin's school, in psychotherapeutical theories of W. Franki, R. May, R. Assajioli, and in some contemporary theories of motivation (J. Nuttin) is discussed. Particular attention is given to the problem of persistence: to the history of corresponding studies, their results and methodology.