Usually a serious academic work can be published in two or three thousand copies in the French-speaking world, which is a bestseller, and a more difficult book like "Structuralism" has been republished seven times, which shows the great influence of this book.
Piaget was a well-known child psychologist, but he was much more than a psychologist, he was also a university scholar who studied mathematics, logic, physics, biology, psychology, sociology, the history of science, and philosophy.
Piaget's important contribution to psychology was that he made Freud's casual and lack of systematic clinical observation more scientific and systematic, so that clinical psychology could develop in the future.
