The author presents a detailed description of A. Maslow's theory of motivation from the point of view of development and transformation of the central concept of this theory - the concept of self-actualization of personality. Five successive interpretations of the concept have been established - self-actualization as: 1) the highest, ultimate level of the development of personality, 2) the highest motivation, 3) the process of personality development, 4) episodic bursts of inspiration, 5) prerequisite of the true Being of personality. Criticisms of western writers in address of the theory are analytically reviewed. Particular attention is given to the issue of the biologistic approach to understanding of the man's nature in Maslow's theory.