But he never shone in school, and Kitty found this intolerable. “Peter was a terrifically sensitive child,” said Harold Cherniss, “and he had a very hard time in school. . . . [But this] had nothing to do with his ability.” In response to Kitty’s nagging, Peter retreated into himself. Serber recalled that when Peter was five or six years old, “he seemed to be starved for affection.” But as a teenager he was just very solemn. “You’d come into the Oppenheimer kitchen,” Serber said, “and Peter would be a shadow . . . trying not to be noticed—that would be Peter.”

