First published in 1959, Metamorphosis remains one of the great works of developmental psychology of the past century. From his thoughtful meditation on the assumptions of classical Freudian psychoanalysis, among them the pleasure and reality principles, the relations of drive and affect, and the nature and causes of infantile amnesia, Schachtel moves on to profound reflections on the senses considered both in terms of their evolving relation to one another during maturation and as variable ingredients in the perception and cognition of the adult.