Hunter S Thompson, the inventor and chief exponent of "gonzo" journalism, who has committed suicide aged 67, was a chronicler of American life since the 1950s, and a compelling and original figure.
Gonzo journalism, a term invented by Thompson, was a chief ingredient in the new journalism of the 1960s and 70s. The respectable, detached, objective tone demanded by mainstream American journalism was, he thought, a powerful ingredient in the banality and dishonesty of American life. It was the failure of journalism to make sense of the 1960s that opened the way for new voices like Thompson's, and new vehicles, like Jann Wenner's Rolling Stone magazine, in which Thompson published some of his most important articles.
Unable, and unwilling, to work within the confines of any institution or periodical, it took Thompson a decade to find the distinctive voice that became one of the most strikingly original in American writing. If the quotes he had to hand were boring, he made up new ones; if the setting lacked somewhat in vividness, that, too, could be fixed. Fantasies were every bit as useful a foundation for his articles as any sober fetish with "the facts". He broke every rule in the book, and was crowned in the New York Times as "our official crazy".
Writing to a friend in November 1963, he used the phrase "fear and loathing" to describe how he felt at the assassination of President John F Kennedy. The phrase was used in his landmark book about Las Vegas in 1973, and repeatedly thereafter. Nuances of its meaning - paranoia, self-absorption, anxiety, rage - made it Thompson's trademark.
While at high school in Louisville, Kentucky, in the 1950s, he read and adored JP Donleavy's raucous novel The Ginger Man, and Jack Kerouac's On The Road. It was the subversive message of both books which hit home. In a childhood marked by family tragedy (his father, an insurance agent, died when his son was 15, leaving the family broke), Thompson went off the rails in a big way. He was unhappy, deeply rebellious, and was guilty of vandalism, break-ins, heavy drinking and petty theft.
At the age of 17, he was sentenced to 60 days in the Louisville children's centre for armed robbery. Refused permission to take his final examinations, he did not graduate from high school. On his release from juvenile detention after 30 days, he bought a case of beer and threw one bottle at a time through the window of the school superintendent who had blocked his return to school.
Over the following decade, Thompson was, by turns, a prankster, an insubordinate air force enlistee, a copyboy at Time magazine and a failed novelist. He worked intermittently on Prince Jellyfish, an autobiographical novel about a boy from Louisville, going to the big city and struggling against the dunces to make his way.
Thompson made a journalistic breakthrough with off-beat profiles. In the 1960s, he wrote pieces about smugglers, bikers, flower children, migrant workers, hobos and drifters. He wrote about politics, and generally regarded politicians as crooks or charlatans - or both.
Richard Nixon was a particular object of his venom. Interviewing him during the presidential election of 1968, he found the sleek and polished performer in the New Hampshire primary was no longer "just another sad old geek limping back for another beating". The new Nixon was "a brute in need of extermination". Thompson felt that Nixon spoke "for the werewolf in us". The Shark Hunt, a collection of Thompson's journalism, was dedicated to the disgraced former President Nixon in 1979: "To Richard Milhous Nixon, who never let me down".
Thompson's first book, an account of the Hell's Angels published in 1967, was a vivid piece of journalism, but it was not yet full-bore gonzo. He spent a year living and riding with the bikers. But he chose to ride a different bike (a BSA instead of the Harley Davidson much loved by the Hell's Angels), he did not wear black leathers, and he tried to keep an element of distance between himself and the club members.
The relationship broke down over the bikers' suspicion that Thompson was making money from his writing, and they wanted a share. He received a savage beating, but came away with a book which overturned every charitable assumption about deviance, while doubting the threat the biker gangs allegedly posed to respectable California.
It was Thompson's immersion in the gang culture of the Hells Angels that announced a powerful new kind of voice in American journalism. Commissions soon flooded in from Esquire and Harper's. The timidity of editors of mainstream magazines drove him on to new heights of verbal inventiveness and outspokenness.
He ran unsuccessfully for sheriff of Pitkin County, Colorado, in 1970, as leader of the Freak Power Movement. An account of the campaign, The Battle Of Aspen, was his first contribution to Rolling Stone.
The age of gonzo officially began with Thompson's account of a drug-fuelled visit to Las Vegas, published in two issues of Rolling Stone, and then issued, to great acclaim, in 1972 as Fear And Loathing In Las Vegas. It was followed by Fear And Loathing: On the Campaign Trail '72 (1973).
In an age when the dutiful books of Theodore H White embodied the best of American political journalism, Thompson - aggressive, cynical and fiercely sceptical - stripped away layers of unquestioning respect for politicians. He was a new kind of participant-observer, who made himself the story. His later books included two substantial collections of letters.
When asked what Thompson would have been without drugs, Jann Wenner shrugged, and replied: "An accountant. No doubt about it." A hero of the counter-culture, Thompson did not easily fall in with liberal pieties. For example, he blamed the American failures in Vietnam on the evil influence of "cowardly faggots and spies". He was also the model for Garry Trudeau's Uncle Duke in the Doonesbury comic strip.
He is survived by his wife Anita and son Juan.
· Hunter Stockton Thompson, writer, born July 18 1937; died February 20 2005