An attempt has been made to analyze and specify L. S. Vygotsky's idea of the proximal zone of child's development in the light of pressing needs of the educational practice. It is pointed out in connection with this that together with such a zone which provides for reproductive independent performance on the part of a pupil, there appears in the process of learning another kind of a zone - that of his creative independence. Formative efficiency of learning is at that directly proportional to the size of this zone (and not only of the proximal zone of development) and inversely proportional to the combination of instructional influences. Introduction of a computer into the instructional process makes it possible to perform accurate operative diagnosis of both zones and thus to purposefully cultivate them.