About the book: 1965 / The fight against old age is one of the main tasks of modern science. How to extend a person’s life, maintain his health, vigor and efficiency? What is needed to prolong life and fight old age? All issues related to the aging of the body are studied by gerontology. The purpose of this work is to acquaint the reader with the basic theories and ideas about the aging process; show in general terms the changes occurring in the human body due to old age. Particular attention is paid to the teachings of I. P. Pavlov and his school. Along with literary data, a significant place in the work is occupied by the materials of the author’s own research on the study of human aging processes, conducted in the gerontology sector of the Academy of Sciences of the BSSR. Designed for physiologists, medical workers and a wide range of people interested in these issues. Editor: Academician of the Academy of Sciences of the BSSR V. A. Leonov