The paper is an attempt to draw attention of professional psychologists to L.S. Vygotsky's first published book "Educational psychology". The goal of creating an objective and exact system of scientific educational psychology, put forward by L.S. Vygotsky, has not lost actuality to this day. Many ideas from L.S. Vygotsky's book can be successfully applied in solving contemporary educational problems, such as instruction and upbringing of children (normal and retarded), psychological research of teaching activity, etc.