Abstract: L. S. Vygotsky(1896—1934) was an outstanding Marxist psychologist in the earlier years of the Soviet Union and founder of the Vygotsky-Leontyev-Luria School. His Theory of Higher-Level Mental Functions is the theoretical base of this School which holds that higher-level mental functions are manifestations of the real nature of human mental activities. What makes the difference between human beings and animals is precisely the fact that human beings possess higher-level mental functions while animals do not.This article analyses the historical background at the time of the emergence of this theory, describes how L. S. Vygotsky developed it in the course of struggles against the advocates of various schools of idealism and mechanism among the psychologists of that time, and discusses specifically the social origin of the Theory of Higher-Level Mental Functions, the Theory of Intermediary and some questions about seats in the brain cortex of higher-level mental functions.The author comments on the contributions made by Vygotsky's Theory of Higher-Level Mental Functions and points out some of its shortcomings.

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