Psychology is a science that studies the laws and mechanisms of people's mental activity. The name of science “psychology” comes from the Greek words: “psyche” (soul), “logos” (teaching), that is, the science of the soul, more precisely, about the inner, subjective world of man. The term “psychology” was proposed by the German scholastic Goklenius at the end of the 16th century.

For a long time, psychology developed as an integral part of philosophy, and only in the middle of the 19th century did it emerge as an independent science. This became possible because psychology was gradually transformed from a descriptive science into an experimental science. At present, psychology is a fairly complex and extensive system of disciplines. In addition to the general psychology that studies the general laws of mental activity, private, applied branches of psychology exist and are rapidly developing. Thus, the group of applied industries that study the laws and mechanisms of the psyche of people engaged in specific types of activity are: the psychology of labor and its relatively independent sections - engineering, aviation and space psychology; psychology of knowledge; pedagogical, military, legal psychology, etc.
Before the operational, investigative, prosecutorial and judicial officers constantly arise many questions, the solution of which requires not only a broad outlook, legal culture, special knowledge and life experience, but also a good knowledge of legal psychology. In order to properly understand the complex relationships of people, their experiences and actions, in complicated situations that are reflected in criminal cases, it is necessary to know the laws of mental life.

Legal psychology includes various areas of scientific knowledge, is an applied science and equally belongs to both psychology and jurisprudence. In the field of public relations regulated by the norms of law, the mental activity of people acquires peculiar features that are caused by the special features of human activity in the sphere of legal regulation. Psychology is the only science capable of providing not only the knowledge of mental activity, but also its management. With the development of society, its value will increase more and more.

The need to turn to psychology, its methods, achievements arises when a specific science, adjacent to psychology or closely related to it, is included in the solution of practical problems. It has this place in pedagogy, medicine and law. Practical activity, as a rule, is realized in concrete actions of concrete people, and how this happens depends largely on their psychological characteristics. Only the need to solve practical problems has led to the emergence and development of social, ethnic, historical and other branches of psychology on the border with social science. It would be, however, diminishing the role of natural in the life and development of the personality, an appeal exclusively to the social aspects of its manifestation. Of course, the study of human biology (anatomy, physiology, anthropology) is inextricably linked with research in the field of psychophysiology, neuropsychology, psychophysics, and other sciences bordering on psychology and natural science.

The whole system of scientific knowledge feels the need to use psychological knowledge, it becomes a link of various fields of science. Psychology links the social sciences and the natural sciences, biology and history, medicine and pedagogy, management and jurisprudence, etc. This determines its place in the system of scientific knowledge.