WHEN HE first heard Techno music, Nicholas Saunders found it "unrelenting and aggressive". Then he discovered the "rave experience". "I followed a friend's advice of moving with the base and ignoring the rest," he says. "Imperceptibly, gradually, I relaxed, melted into the ambience, and knew I was part of it all. It was as though I was surrounded by fellow members of an exclusive tribe bonded by some shared understanding, yet full membership was mine for the pounds 10 ticket and pounds 15 Ecstasy tablet."

Saunders is not your typical raver. Balding, mild-mannered and pushing 60, he looks more like a cleric than a guru of the Ecstasy generation. But put him in a room full of clubbers a third his age, and he'll be kept busy for hours, answering questions and exchanging stories.

Since the publication in 1993 of his underground book E for Ecstasy, Saunders has become popular in the rave scene. He now writes regularly for Eternity, the dance magazine, and lectures around the country - even managing an appearance at the Edinburgh festival. His new book, Ecstasy and the Dance Culture, an update of E for Ecstasy, is due out next week.

Self-published, the book is a bizarre combination of scientific and sociological theories and personal anecdotes, with a strangely inconsistent writing style - intelligent and questioning one minute, daft and indulgent the next, with a tendency to include rather hippie, self-exploratory passages. For example, two pages of before and after drawings by "artists" on Ecstasy is more than a little reminiscent of stoned schoolboys designing album covers.

But to dismiss him as a self-indulgent "vanity" publisher would be unfair. The first Ecstasy book sold 10,000 copies. It is due to be published in San Francisco by Ed Rosenthal, and by other publishers in France, Germany, Italy and Russia. And it is not so much vanity that has motivated Saunders, as a conviction that Ecstacy has therapeutic benefits. "Ecstasy got me out of a rut," he says. "I truly believe that it has improved the quality of my life."

Having been converted, he set out spreading the word. He speaks angrily of the tabloid press: "They knew that most Ecstasy deaths are due to overheating; not to tell people how to avoid dying, that is utterly irresponsible."

So Saunders commissioned tests on street samples of the drug, the results of which he publishes, both in his new book, and free on the Internet. Ian Wardle, of the drugs agency Lifeline, applauds the testing service, while remaining cynical about the man: "For all his friendly, amateurish, dilettante-ism," he says, "Saunders is an astute businessman."

Ecstacy users, though, have lapped it up. One, who asks not to be named, comments: "The Internet site's really useful. I didn't buy E the other night, because it was one of those pink, strawberry ones [described by Saunders as a potentially dangerous mixture of three different drugs], but someone else did, and was really sick." Andy Medlock, another dance- scene regular, read E for Ecstasy as soon as it was published. "I'd really like to meet the man," he says. "He looks at the scene in a positive, informative way."

Saunders describes himself as a "typical dropout", who left mechanical engineering in the Sixties to join the hippie trail to success. In the Seventies he published the radical guidebook Alternative London for people who aspired to alternative lifestyles. The first of its kind, it contained information ranging from how to fix your squat's plumbing to Buddhism for beginners and sold almost 300,000 copies.

Going on to found the Neal's Yard group of wholefood shops, he bought up properties in what was then a run-down area of Covent Garden and ran a series of co-operatives. But, like a true hippie, profit has never been his overriding motive and most of the businesses in the yard are now independent.

He still lives and works in Neal's Yard, running a small desk-top publishing studio. His flat, like his books, is an odd mixture of styles. A modern, minimalist kitchen and uncluttered work station suggests the home of a researcher. But a glance at the ceiling reveals another, unmistakably psychedelic influence. Huge, pink and brown pear shaped pods that turn out to be rooms come out of the ceiling. As you walk up the staircase it somehow spirals inside one of these pods and turns into the living- room couch.

Saunders has a slightly scientific air, but speaks about Ecstasy with a proselytising zeal. He has often been likened to the American Timothy Leary, who wrote about LSD in the Sixties - a comparison he doesn't care for. "I don't have much respect for Tim Leary - he did tremendous harm," he says, citing uncontrolled experiments by Leary which Saunders feels alienated many serious researchers of LSD from the scientific establishment.

But Saunders' own work has not been without criticism. While his comparison of the risk of death from taking Ecstasy to "taking five rides at a fairground" - has been vindicated by estimates done by the drugs agency, Lifeline, his open-ended conclusions about its effects on human brains has been deemed irresponsible by physicians working in the field.

According to Tom Fahy, consultant psychiatrist in drugs research at Maudsley NHS Trust: "The research simply hasn't been done. To give a fairly uninhibited endorsement of the drug is potentially dangerous - there is a body of animal research showing that large doses of Ecstasy cause permanent brain damage. With this sort of evidence there's no way drug regulatory bodies would approve its use in humans." Psychiatric problems have been noted in Ecstasy users, by people such as Fahy and Dr John Henry of the National Poisons Unit. And the problem of the as yet unknown long-term effects in humans remain.

But Saunders is undaunted. "Yes, I think the toxicity problem is real. But sooner or later, someone will come up with a drug which is non-toxic," he says with a smile. "Pleasure without the pain."

8 `Ecstacy and the Dance Culture' is publised 4 September. Available from Neal's Yard DTP Studio (Telephone: 0171-379 5113), pounds 9.95