The book provides basic information on the psychology of individual differences, which are considered in differential psychology and differential psychophysiology. Particular attention is paid to: various approaches to generalized individual characteristics of a person - types of temperament and personality; features of the manifestation of the properties of the nervous system; individual differences in behavior; the effectiveness of human activity depending on his individual characteristics; the connection between individual characteristics and predisposition to various diseases. The appendix includes methods for studying individual characteristics of a person and an extensive list of references, which may be useful to those who want to study the issues presented in the book in more depth. The publication is addressed to practical psychologists, doctors, and psychology teachers at universities. It will be of interest to physiologists, as well as teachers, since it allows us to understand the natural foundations of the abilities and behavior of students, the need for an individual approach to them in the process of training and education.