This book delivers finely written and observed, often harrowing, personal reporting on experiences with exotic psychedelic drugs. It also pushes a larger message that the reporting doesn't support -- and in some ways actively contradicts.

Daniel Pinchbeck, a young Manhattan intellectual, son of an abstract expressionist painter, Peter Pinchbeck, and a Beat generation memoirist, Joyce Johnson, found himself "yearning for meaning and spiritual truth in a world that seemed devoid of both." Driven by this sense of lack -- and by an assignment from Vibe magazine -- he ventured into Gabon to participate in the ancient iboga ceremony. Derived from the rootbark of an African tree, iboga is known to provide visions and psychological insights that are said to cure drug addictions. Pinchbeck saw visions, realized that he drank too much, and started to think that his dead grandmother was haunting him.

That's just the beginning of his psychedelic travelogue. The book follows him on trips to Huautla, Mexico, to eat psychedelic mushrooms, and to the Ecuadorean Amazon to partake in an ayahuasca ceremony.

He took a side trip to the Burning Man festival, where wealthy computer-industry types chatted with him about designer psychedelics. He attended a conference on entheobotany -- the study of plants that give insight into God -- that served as his entree to the weirdest drugs of all: DMT (dimethyltryptamine) and DPT (dipropyltryptamine). Pinchbeck describes the effects of smoking DMT as "being shot from a cannon into another dimension." Users report feeling as if it rips back the veil of reality, revealing what Pinchbeck speculates are "superconscious entities who created and maintain our universe."

After taking DPT a couple of times -- the first time he pegged it as "evil...the wrong doorway" -- he decided that his apartment was haunted. In his silverware drawer he saw grotesque insects that he thought must be of supernatural origin. He came to "strongly suspect an ordinary death is not the worst thing that can happen to a human being." Panicked, and with the help of a mystical stripper he befriended at Burning Man, he performed a ritual to cleanse his apartment of the evil vibes before his girlfriend and infant child returned.

Pinchbeck's reporting is fascinating and entertaining, but he doesn't let it stand alone. He insists that psychedelics have something valuable to teach us about the world of the spirit -- that they can make us "spiritual warriors" and "break the spell of our culture's death-trap deceptions." But his iboga shaman threatened and extorted from his American charges; the ayahuasca shaman waved a rifle and threatened to kill whoever stole his boat. They do not seem, after all, so different in character from those in the visionless West.

To be sure, the psychedelic experience casts many things about our understanding of consciousness and reality into question. But Pinchbeck neglects to take seriously that he is ingesting chemicals that affect the brain. The ability of psychoactive-chemical consumption to create fascinatingly strange perceptual and cognitive effects could be used to support a purely biochemical explanation of human consciousness.

But Pinchbeck takes the opposite tack. He insists that these substances are teaching us something about spiritual reality as opposed to something about consciousness. These currently illegal substances hold plenty of promise for purposes ranging from the therapeutic to the cognitive to the purely hedonic. They do have much to teach about how our brains work, and provide valuably unique experiences besides. It's a crime, as Pinchbeck rightly notes, that laws prevent above-board research into their nature and effects.

But Pinchbeck doesn't merely argue for personal freedom in using drugs. He calls Timothy Leary a "villain" for his freewheeling approach to bringing the psychedelic experience to the people. Pinchbeck plumps for the tribal shamanic tradition, which in modern terms is the mandarin one -- the idea that these substances are not for the masses, but for an elite guild. He writes at times as if he would prefer a Federal Bureau of Shamans to pure psychedelic liberty.

Old heads know: Sometimes nothing can be as dull as other people's trips. Pinchbeck succeeds in making his fascinating. Still, there is something inherently personal, incommunicable and often evanescent about psychedelic insights. So from an outside perspective, the reader sees Pinchbeck changing from an ennui-filled modern to someone frightened out of his wits by eldritch insects. He went around the world, took part in ancient and hallowed ceremonies, and learned that corporations are bad and humans are raping the earth. (One suspects that a young Manhattan intellectual might have pretty much felt that way before all the drugs.)

Although he is a great reporter, when it comes to making the case for the spiritual wonders of psychedelics he is unpersuasive. His book does convey that there are vital, often incredible things about psychedelics that we don 't understand -- and should try to. But when he tries to glean spiritual significance from these possibilities, Pinchbeck seems to be trying to lay his bum trips on his readers.