The book is dedicated to the work of the classic of psychology Jean Piaget. In addition to the fundamental works of Piaget, the collection contains studies of domestic and foreign authors analyzing the theoretical and experimental contribution of the founder of the Geneva School to the study of the stages of development of intelligence in ontogenesis. For the first time in Russian literature, Piaget's work is presented so voluminously, in a historical perspective and in comparison with the views of his most authoritative critics - psychologists and philosophers (L.S. Vygotsky, P.Ya. Galperin, D.B. Elkonin, V.V. Davydov and others).