When the Harvard psychologist and psychedelic explorer Timothy Leary first met the Beat poet Allen Ginsberg in 1960, he welcomed Ginsberg’s participation in the drug experiments he was conducting at the university.

“The first time I took psilocybin — 10 pills — was in the fireside social setting in Cambridge,” Ginsberg wrote in a blow-by-blow description of his experience taking synthesized hallucinogenic mushrooms at Leary’s stately home. At one point Ginsberg, naked and nauseated, began to feel scared, but then “Professor Leary came into my room, looked in my eyes and said I was a great man.”

Ginsberg’s “session record,” composed for Leary’s research, was in one of the 335 boxes of papers, videotapes, photographs and more that the New York Public Library is planning to announce that it has purchased from the Leary estate. The material documents the evolution of the tweedy middle-aged academic into a drug guru, international outlaw, gubernatorial candidate, computer software designer and progenitor of the Me Decade’s self-absorbed interest in self-help....

The meeting between Ginsberg and Leary marked an anchor point in the history of the 1960s drug-soaked counterculture. Leary, the credentialed purveyor of hallucinatory drugs, was suddenly invited into the center of the artistic, social and sexual avant-garde. It was Ginsberg who helped convince Leary that he should bring the psychedelic revolution to the masses, rather than keep it among an elite group. Filling out one of Leary’s research questionnaires in May 1962 the poet Charles Olson wrote that psilocybin “creates the love feast,” and “should be available to anyone.”...