AS A chronicler of the America of the 1960s and 1970s, Hunter S. Thompson was far from being the first apostle of the counter-culture. But in what became known as gonzo journalism (later somewhat stuffily to be redefined as “the New Journalism”) he brought to the process of reporting the era an irresistible immediacy.

His first book, Hell’s Angels (1966), had involved him in living and breathing the same air as his subjects, to produce a chronicle of terrible conviction — and one which seemed almost to frighten its author. (It also left him with an enduring love of the motor cycle.) But it was with Fear and Loathing in Las Vegas (1972), illustrated by Ralph Steadman, that Thompson redefined the role of the journalist, as not merely commentator, but as actor and participant in the manic social drama of his times.

In Fear and Loathing, which had its genesis in two long articles Thompson wrote for the bible of the counterculture, Rolling Stone, in 1971, we are made suddenly to realise that we are not to go to the reporter for objectivity, but for the ventilation of articulate prejudice. Its protagonists, setting off from California to cover some fuzzily defined event in Nevada’s gambling capital for “a fashionable sporting magazine in New York”, are manifestly not men to whom anyone would entrust either the welfare of a young person or a newpaper expense account.

As described to us in the opening moments of this piece of reportage, the protagonists’ misuse of the latter exceeds all previously sanctioned excesses on the expense account front, as treated in the fiction of newspaper offices. “The sporting editors had given me $300 in cash, most of which was already spent on extremely dangerous drugs. 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 full of cocaine . . .” A hitch-hiking youth to whom they offer a lift to get him off the baking highway is glad to escape from this alarming company at the first opportunity, by leaping out of the back of the car. Arrived in Las Vegas, the protagonists continue to cut a manic swath through all known conventions.

Thompson’s prejudiced standpoint, here defined in the persona of his protagonist Raoul Duke, becomes the filter through which the world of modern America is viewed. And yet the sum effect of the process is to leave the reader with the conviction not that the Thompson protagonist is mad — or at least no madder than anyone else — but that he is merely adopting a picaresque persona as a self-defence against the insane world in which he finds himself. Las Vegas and all it stands for is comprehensively excoriated in a book whose subtitle is A Savage Journey to the Heart of the American Dream. Thomson makes sheer rage effective as a vehicle for truthful perceptions.

The next five years were really Thompson’s heyday, as he revelled in his role as Rolling Stone’s chief political commentator — having somehow, though lacking much formal education, metamorphosed into “Dr Hunter S. Thompson”. His columns — given the space which that excellent journal habitually accorded them — read like increasingly alarming rollercoaster rides, from which the danger of falling off seemed to increase exponentially the longer they went on. Thus Thompson, covering the 1972 presidential election campaign, might break off to road-test a version of the awesome Vincent Black Shadow motorbike, openly lamenting to us the readers over his inability to stick to the topic for which his editors are paying him.

Apart from this tangential ferment, his political opinions were delivered with brutal bluntness. Thus Nixon in the midst of his entourage was described as representing “that dark, venal and incurably violent side” of America, while Senator Hubert Humphrey was dismissed as “a shallow, contemptible and hopelessly dishonest old hack”. Such breathtaking pungency refreshingly recalled the gloves-off political journalism of previous centuries.

Inevitably, perhaps, an intensity of this type could not be sustained at a level where it was consistently plausible. As the 1970s went on a certain exhaustion was detectable in the powers of invention, and in the purity of the perceptions. Unlike other exponents of New Journalism, notable among them Norman Mailer and Tom Wolfe, Thompson undoubtedly ran out of steam, becoming an object of parody, as he was in Gary Trudeau’s balding Doonesbury cartoon character “Uncle Duke”. But in liberating the journalist from the canons of “objectivity” in the first place, Thompson was able to bring to his reporting all the individual’s sense of bewilderment in a hideous and complex world.

Hunter Stockton Thompson was born the son of an insurance agent in Louisville, Kentucky, in 1937. He was educated at a local state school, from where he was drafted for service into the US Air Force. His introduction to journalism was covering sports events for a service newspaper at Eglin air base in Florida.

Back in civilian life, he had several jobs on local small-town newspapers before, in 1960, going to the Caribbean as correspondent for the New York Herald Tribune. There followed two years as South American correspondent for the National Observer, the job giving him an insight into various forms of criminal activity germane to the area, including smuggling, gang murder, banditry and kidnapping.

He had already had a period in San Francisco, but his move back there in 1963 was decisive on his outlook. He became steeped in the burgeoning hippie culture, and the violent intolerance it generated, both within itself, from officialdom and from such groups as the Hell’s Angels. The vernacular of both hippies and Hell’s Angels became part of the fibre of his writing style in those days, though, when he was able to stand back, he was not inclined to glamorise either group. His period with the latter he was eventually to describe as “a bad trip”. His book on the subject expressed his bemusement at a form of popular culture which seemed to be the victim of its dimly understood but all-consuming hostility to whatever it regarded as alien to it. Hell’s Angels won Thompson immediate fame, through its airing of a subject which revealed to the nation an “unspeakable” subculture dwelling within it.

Thompson’s association with Rolling Stone began in 1970, and the extensive articles he was able to write for it provided the ideal platform for his unique style and aperçus. After Fear and Loathing in Las Vegas, his acrid series for Rolling Stone which covered the 1972 campaign trail became a book, Fear and Loathing on the Campaign Trail ’72, which was published in 1973. Thompson, who had thrown the weight of his sympathies behind the Democrat nominee, George McGovern, did not attempt to disguise his loathing of the Nixon camp.

The Great Shark Hunt, which was published in 1979, collected many of the pieces written for Rolling Stone and for other journals in the 1970s. Thompson was always famously at loggerheads with his employers at the magazine for his approximate methods of accounting for expenses.

Among Thompson’s later works were: (with Steadman) The Curse of Lono (1983); Generation of Swine (1988); Better Than Sex (1993) and Fear and Loathing in America (2000). The Rum Diary, which appeared in 1998, was a novel he had written in the 1950s but not published.

Thompson, who besides motorcycles, enjoyed a passion for firearms and wrote eloquently on the qualities of the Smith and Wesson .44 Magnum Model 29 revolver, was a member of the National Rifle Association. He had, in 1970, run to become sheriff of Pitkin County, Colorado, where he lived. He was found dead at his home of an apparently self-inflicted gunshot wound.

Thompson is survived by his wife of two years, Anita, and by the son of his first marriage, in 1963, to Sandy Conklin.

Hunter S. Thompson, writer, was born on July 18, 1937. He was found dead of a gunshot wound on February 20, 2005, aged 67.