When Sigmund Freud was nearly seventy and reflecting upon his life, he noted in Selbstdarstellung that during his youth he was consumed with a passion for knowledge that had more to do with human relationships than with natural objects. This collection of nearly eighty letters, written by Freud to his boyhood chum Eduard Silberstein, attests to that earlier, more whimsical life and to the existence of a deeply sensitive, observant youth.

The letters were composed over a period of ten years during which Freud and Silberstein attended secondary school and later the university in...