The good Lord—or maybe it was natural selection, but, when you look at the outcome, how plausible is that, really?—gave us, in addition to the birds of the air and the beasts of the field, the fantastic variety of fungi with which we share this awesome planet: yeasts, rusts, mildews, mushrooms, and molds. Among them is ergot, a fungus that destroys cereal grasses, particularly rye, and that, when eaten, can cause hallucinations. Ergot is the natural source of lysergic acid, from which lysergic acid diethylamide is readily synthesized—LSD. What purpose, divine or adaptive, this substance might serve was once the subject of a learned debate that engaged scientists, government officials, psychiatrists, intellectuals, and a few gold-plated egomaniacs. Timothy Leary was one of the egomaniacs.

Leary belonged to what we reverently refer to as the Greatest Generation, that cohort of Americans who eluded most of the deprivations of the Depression, grew fat in the affluence of the postwar years, and then preached hedonism and truancy to the baby-boom generation, which has taken the blame ever since. Great Ones, we salute you! Leary was born in 1920, in Springfield, Massachusetts, which is also the home town of Dr. Seuss, of whose most famous creation Leary was in many respects the human analogue—a grinning, charismatic, completely irresponsible Lord of Misrule. Leary’s father was a dentist whose career was ruined by alcoholism; he abandoned the family in 1934, ending up as a steward in the merchant marine. Leary’s mother was a fierce guardian of her son’s interests, which required a considerable amount of guarding. Leary was intelligent, and he did not lack ambition, but—as Robert Greenfield meticulously documents in his exhaustive biography, “Timothy Leary” (Harcourt; $28)—his education was a game of chutes and ladders: Holy Cross (where he came near to flunking out after two years), West Point (from which he was obliged to withdraw after being charged with a violation of the honor code), the University of Alabama (from which he was expelled for spending a night in the women’s dorm), the University of Illinois (from which he was drafted into the Army, where he served in a clinic for the rehabilitation of the deaf, in Pennsylvania), Alabama again (which he talked his way back into and from which he finally graduated, by taking correspondence courses), Washington State University (where he got a master’s degree), and, with the help of the G.I. Bill (a welfare fund for Great Ones), Berkeley, from which, now married and with two children, he received a Ph.D. in psychology, in 1950.

There was no more opportune moment to become a psychologist. Psychology in the nineteen-fifties played the role for many people that genetics does today. “It’s all in your head” has the same appeal as “It’s all in the genes”: an explanation for the way things are that does not threaten the way things are. Why should someone feel unhappy or engage in antisocial behavior when that person is living in the freest and most prosperous nation on earth? It can’t be the system! There must be a flaw in the wiring somewhere. So the postwar years were a slack time for political activism and a boom time for psychiatry. The National Institute of Mental Health, founded in 1946, became the fastest-growing of the seven divisions of the National Institutes of Health, awarding psychologists grants to study problems like alcoholism, juvenile delinquency, and television violence. Ego psychology, a therapy aimed at helping people adapt and adjust, was the dominant school in American psychoanalysis. By 1955, half of the hospital beds in the United States were occupied by patients diagnosed as mentally ill.

The belief that deviance and dissent could be “cured” by a little psychiatric social work (“This boy don’t need a judge—he needs an analyst’s care!”) is consistent with our retrospective sense of the nineteen-fifties as an age of conformity. The darker version—argued, for example, by Eli Zaretsky in his valuable cultural history of psychoanalysis, “Secrets of the Soul”—is that psychiatry became one of the instruments of soft coercion which liberal societies use to keep their citizens in line. But, as Zaretsky also points out, leading critics of conformity and normalcy—Herbert Marcuse, Allen Ginsberg, Norman Mailer, Norman O. Brown, Paul Goodman, Wilhelm Reich—thought that it was all in the head, too. For them, normalcy was the neurosis, for which they prescribed various means of personal liberation, from better drugs to better orgasms. In the early years of the Cold War, personal radicalism, revolution in the head and in the bed, was the safer radicalism. The political kind could get you blacklisted.

Leary spent the first part of his career doing normative psychology, the work of assessment, measurement, and control; he spent the second as one of the leading proselytizers of alternative psychology, the pop psychology of consciousness expansion and nonconformity. But one enterprise was the flip side of the other, and Greenfield’s conclusion, somewhat sorrowfully reached, is that Leary was never serious about either. The only things Leary was serious about were pleasure and renown. He underwent no fundamental transformation when he left the academic world for the counterculture. He liked women, he liked being the center of attention, and he liked to get high. He simply changed the means of intoxication. Like many people in those days, he started out on Burgundy but soon hit the harder stuff.

The popular conception of Leary is that he was a distinguished academic who went off the deep end, a Harvard professor who blew his mind. For obvious reasons, this account suited Leary, and even Greenfield refers to him repeatedly as a Harvard professor (as does the Columbia Encyclopædia). Leary did teach at Harvard, but was not a professor. He began his career at Kaiser Permanente Hospital in Oakland, where he was the director of clinical research and psychology. His early work involved personality tests; his first book, “The Interpersonal Diagnosis of Personality,” came out in 1957. It was a success, but, Greenfield says, some of Leary’s colleagues felt that he had failed to credit their research. Even then, he seems to have been blessed with an incapacity for shame, a gift for which he had many occasions to be thankful.

Leary had already had a bad run of personal troubles. His first wife had committed suicide on his thirty-fifth birthday. (When she complained, during a night of heavy drinking, about his having a mistress, he is supposed to have said, “That’s your problem.”) Leary then married the mistress, but, soon afterward, he struck her, the landlady called the cops, and the marriage ended. In 1956, Leary’s father, with whom he had just reconnected, died, destitute, in New York City. Soon after, a former faculty adviser, a married man with whom Greenfield believes Leary was having a sexual affair, was arrested while cruising a public men’s room, and Leary had a nervous breakdown. He travelled to Europe, where he met David McClelland, the director of the Center for Personality Research at Harvard, who was on a sabbatical. McClelland was trying to start a Ph.D. program in clinical psychology, and, impressed by Leary’s charm and intelligence, he offered him a lectureship for the 1959-60 academic year. Leary accepted, and moved to Cambridge. At the end of the year, McClelland advised him to cultivate a less cavalier notion of science, but he renewed Leary’s appointment. That summer, Leary went to Mexico, and there, for the first time, he ate some “magic mushrooms.” He found the experience entirely enchanting, and when he returned to Cambridge he set up, with McClelland’s approval, the Harvard Psychedelic Project.