In the spring of 1943, a 37-year-old Swiss chemist named Albert Hofmann had “a peculiar presentiment.” He believed that he had missed something in 1938, the year when he first synthesized the twenty-fifth compound of the lysergic acid diethylamide series, LSD-25. For eight years at Sandoz Pharmaceuticals, Hofmann was in charge of the ergot project, which involved synthesizing ergotamine...