I first read Thompson’s Fear and Loathing in the late 1970s and being as callow and inexperienced as most teenagers, I took it for a mostly factual exploit (along with many older readers who didn’t have my excuse for gullibility). I passed the book on to one of my friends who became mildly obsessed with “Raoul Duke” and the adventures recounted in the book. I’ve long since lost touch with him, but I’m sure he’d be horribly disappointed to discover that Thompson probably imagined 90% of it:

We were somewhere around Barstow on the edge of the desert when the drugs began to take hold. I remember saying something like “I feel a bit lightheaded; maybe you should drive …” And suddenly there was a terrible roar all around us and the sky was full of what looked like huge bats, all swooping and screeching and diving around the car, which was going about a hundred miles an hour with the top down to Las Vegas.

From the outset, Fear and Loathing in Las Vegas is an outrageous and darkly amusing tale of two crazed men turned loose in the world’s capital of decadence. Raoul Duke and Doctor Gonzo, clearly based upon Thompson and Acosta, are carrying a veritable pharmacopoeia in the trunk of their rented car, and throughout the novel they abuse a litany of substances as they stumble through casinos, bars, and hotels terrorising staff and patrons alike. Though Duke and Gonzo are, like the real Thompson and Acosta, tasked with covering the Mint 400, their assignment is quickly lost in the carnage. Near the end of the book, Duke admits he “didn’t even know who’d won the race.”

If you are unfamiliar with Thompson’s work, you may wonder why it matters that their efforts to complete a minor assignment ended in failure. Authors like Ernest Hemingway had mined their journalistic experience for material to incorporate into their fiction, so it is hardly unusual that Thompson would find inspiration for a novel whilst covering the Mint 400. But his approach with this book went beyond mere inspiration. Throughout Fear and Loathing, reality and imagination are blurred to the extent that no one really has much idea of what really happened on their trip.

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In this letter, he made the startling confession that Fear and Loathing had not merely exaggerated the debauchery that took place in Vegas, but that there had in fact been no drugs at all. Could this really be true? Was the most notorious drug book of its era really inspired by a drug-free journey?

Before we can answer that, it is important to note the chronology of events on which the book was based. Whilst the book portrays the two men tearing apart hotels and casinos over a period of several days, there were in fact two distinct trips. First, they went to cover the Mint 400 on Mach 21st–23rd, then they returned for the National District Attorneys’ Conference on Narcotics and Dangerous Drugs on April 25th–29th. Thompson simply rolled the two events together into a single narrative. The evidence suggests that, during the first trip, Thompson and Acosta drank heavily and perhaps smoked a little pot, but certainly did no serious drug-taking. The famed pharmacopeia in the trunk of their convertible was fictitious:

The trunk of the car looked like a mobile police narcotics lab. We had two bags of grass, seventy-five pellets of mescaline, five sheets of high-powered blotter acid, a salt shaker half full of cocaine, and a whole galaxy of multi-colored uppers, downers, screamers, laughers … and also a quart of tequila, a quart of rum, a case of Budweiser, a pint of raw ether and two dozen amyls.

As tempting as it is to believe that this existed, it was a product of Thompson’s prodigious imagination. He was, however, keen to keep his readers in the dark, hence his letter to Silberman and the inclusion of his photo on the back cover. Since childhood, he had been obsessed with appearing as an outlaw, yet real outlaws never explicitly said that’s what they were. They merely hinted at it.

Of course, Thompson’s “drug-diet” did consist of various illegal substances, which made his descriptions of their effects rather convincing, but not only did he remain mostly drug-free in Vegas, he also wrote the novel with little more than beer and tobacco in his system. Back home in Colorado, he polished his story carefully through many drafts. The result was a far more intelligent and coherent work than almost anything else he published.

It was only during the second of the two trips that they began to consume drugs, but even then their indulgence was mild when compared with Duke and Gonzo’s extravagant excesses. They had marijuana, a few pills, and possibly some mescaline, but nothing else. His descriptions of LSD came from experiments several years earlier, the parts about adrenochrome were entirely fabricated, and — surprisingly — Thompson had not yet tried cocaine by 1971.