Key aspects of studying of understanding by each other people in psychological science are presented in the monograph. History of development of this subject is reflected in domestic and foreign psychology, approaches to definition of the concept "understanding of other person", understanding accuracy questions, his types and levels, the factors influencing him and also a number of the methods allowing to define a level of development at the person of ability to understanding of other people are considered. Results of the empirical research on a problem of understanding and misunderstanding by each other people conducted by the author are given.