The book offered to the reader is devoted to only one facet of the preliminary investigation - the psychology of interrogation. It was the result of many years of practical work of the author in the prosecutor's office and the court, as well as pedagogical activity. When writing it, the latest studies of Soviet psychologists and the results of experiments conducted by the author in the laboratory of forensic psychology at the Department of Criminalistics of the Law Faculty of Kazakh State University were used. The work reveals the essence of interrogation from the point of view of psychological, its components are distinguished and the psychological and information processes that occur during the production of this investigative action are described. The author tried to show the basic prerequisites and patterns of interrogation, bearing in mind that the creative and effective use of psychological knowledge in practice remains the business of each investigator.