From Piaget's Introduction: “The aim of this little book is … to sound a note of warning. … It does not claim to be more than the testimony of a man who has been tempted by speculation and who almost devoted his life to it, but who understood its dangers, its illusions, and its many errors and wishes to communicate his experiences and justify his painfully acquired convictions.”
Jean Piaget (1896 - 1980) was a Swiss philosopher, natural scientist and developmental theorist, well known for his work studying children, his theory of cognitive development, and his epistemological view called "genetic epistemology." In 1955, he created the International Centre for Genetic Epistemology in Geneva and directed it until his death in 1980. According to Ernst von Glasersfeld, Jean Piaget was "the great pioneer of the constructivist theory of knowing."