George Carlin, who has died aged 71, made his name in the United States in the 1970s as a hip counterculture comedian in the tradition of Lenny Bruce.
An excellent mimic, Carlin had started his career as a relatively conventional comedian in the 1960s before becoming bored with what he called "wearing the dumb tuxedo and entertaining middle-class morons".
Having turned his attention to the satirical treatment of political and social issues -- liberally laced with four-letter words in his 'Seven Words You Can Never Say On TV' routine -- he found a new lease of life, and went down particularly well on university campuses.
George Denis Patrick Carlin was born in the Bronx on May 12, 1937 and grew up in Manhattan.
His father, who worked in the advertising department of the New York Sun, died when George was two, and he and his elder brother were brought up by their mother, Mary, who supported the family through secretarial work.
"When I was a kid," Carlin later recalled, "I knew I wanted to make people laugh. Being a class clown was a good way to attract attention, to get approval. It was fun, people liked you, made you popular." His mother bought him a tape recorder, which he used to hone his skills as a comic.
After dropping out of high school, George joined the US Air Force in 1954. While based in Louisiana, where he was serving as a radar computer mechanic, he spent his spare time working as an off-base disc jockey for a radio station. Then, in 1957, having left the Air Force, he became an announcer with WEZE radio station in Boston.
He was relieved of this job after he took the station's only mobile news car on a trip to New York to buy marijuana (while he was thus employed, a riot broke out at Massachusetts State Prison).
Carlin next worked for KXOL at Fort Worth, Texas, hosting a pop music programme, and while there he established a comedy act with one of the newscasters, Jack Burns. In the early 1960s Carlin and Burns became DJs on a morning radio show in Hollywood, taking their act to a coffee bar in the evenings.
They impressed Lenny Bruce, who put them in touch with an agent, and they appeared on The Tonight Show Starring Johnny Carson and released a record before splitting up in 1962.
For a few years Carlin's career was in a trough. Then, in 1965, he appeared on Merv Griffin's television show, after which he became a regular with Johnny Carson, mainly delivering spoof newscasts.
By 1970, however, he had become restless. Having grown long hair and a beard, he began to base his humour on new material, such as Richard Nixon, drugs, the Vietnam war and American consumerism. At one gig, in Wisconsin, the audience was so hostile that the management -- fearful for his safety -- cut short his act.
In 1972 Carlin was arrested in Milwaukee after performing his 'Seven Words You Can Never Use on Television'.
A charge of public profanity was, however, dismissed by a judge. When the material was later played on a New York radio station, it resulted in a Supreme Court ruling, in 1978, upholding the government's authority to sanction stations for broadcasting offensive language during the hours when children might be listening.
In all, Carlin produced 23 comedy albums, 14 specials for US TV and three books. He appeared on The Tonight Show on more than 130 occasions, as well as in several films.
He won four Grammy awards for his albums and was nominated for five Emmys. Only last Tuesday it was announced that he was to be awarded the 11th annual Mark Twain Prize for American Humour.