The textbook reflects modern views on the organization of normal physiological functions. In contrast to traditional textbooks on physiology that describe the physiological properties of particular organs, this textbook provides a systematic basis for the formation of the functions of the entire body, its homeostatic, behavioral, and mental processes. The textbook presents the long-term experience in teaching a course of normal physiology at the Department of Normal Physiology at the I.M. Sechenov First Moscow State Medical University. Recommended by the I.M. Sechenov First Moscow State Medical University as a textbook for students of institutions of higher professional education.