Hunter S. Thompson was a journalist/author from the U.S.A who gave birth to "Gonzo" journalism. "Gonzo" differed from most types of journalism because instead of being a witness or using sources, he would immerse himself in the story to a point where he became a central figure within the events that took place. This first person style of journalism inspired many in years to come, i.e, Louis Theroux and other investigative journalists have adopted this style to report on modern day social events.
In "fear and loathing in las vegas" he exploited his reputation as a journalist and wrote a story which people automatically perceived to be truth due to his journalistic background. Even though there are aspects of truth in the book, it was in essence, fiction.