Late night talk in the first three decades of U.S. television was dominated by The Tonight Show and, for the majority of that time, by Johnny Carson. However, during the 1980s and early 1990s, the late-night landscape began to change as more talk shows took to the air. Change was accelerated by the appeal of David Letterman and a combination of other factors, including the relative inexpensiveness of producing such shows. audience interest in celebrity and entertainment gossip. and an overall increased reliance in U.S. culture on the talk show as a forum for information and debate about the important, as well as unimportant, issues of the day. The late-night talk genre expanded as network competitors and comrades sought the kind of success that was originally the province of The Tonight Show.

     Each of The Tonight Show's principal hosts has brought his own unique talent and title to the program. All of the shows have featured an opening monologue, a sidekick or co host, in-house musicians. and cadre of guest hosts. Steve Allen's Tonight! featured his musical talents and penchant for a distinctive brand of comedy. He was well known for performing his own musical numbers on the piano and for humorous antics such as on-the-street improvisations and bantering with the audience. both of which were forerunners to the kinds of comedy stunts that became a staple much later on Late Night with David Letterman, also on NBC. In 1957 Allen left Tonight! to concentrate on another variety show he hosted on Sunday evenings.

     Allen's version of the show was immediately followed by the unsuccessful magazine format, Tonight:America After Dark, which lasted only a few weeks. That show was led by Jack Lescoulie, but he was never the central figure Allen had been. Essentially, Lescoulie introduced the segments and correspondents around the nation.

     In July 1957 Jack Paar took over as new host of The Jack Paar Show. Paar brought the show back to its in­ studio interview format. More a conversationalist than comedian, Paar drew audiences to his show by bringing on interesting guests. from entertainers to politicians. Audiences also watched for the controversy that occasionally erupted on the show. Paar did not shy away from politics or confrontation and often became emotionally involved with his subject matter and guests. He had a few stormy run-ins. both on camera and off, and finally left the show following controversy surrounding his broadcast from the Berlin Wall in 1962.

     With another change in hosts came a complete change in tone and style. In October 1962 Johnny Carson took over as host of The Tonight Show Starring Johnny Carson. Carson was more emotionally detached and less political than Paar; like Allen, he was a comic. Named the "king of late night," Carson hosted the show for 30 years, from 1962 to 1992. During that time, the show moved from New York City to Burbank, California. Carson was known for his glib sense of humor and his middle-American appeal, and quickly recognized his increasing popularity as well as the strain of doing comedy and talk five nights a week. He threatened to leave the show, but he was lured back with a generous offer that included a huge salary increase and more time off. Guest hosts during Carson's tenure included comedian Joan Rivers, Jay Leno, and David Letterman.

     When Carson retired, Leno was appointed the next principal host of the series, now named The Tonight Show with Jay Leno. A well-known stand-up comedian, Leno brought to the show his own writers and comic style. showcasing the latter in his opening monologues. banter with guests. and unique comic bits.

     Changes in Leno's show have reflected major changes in television since the medium's earlier days. For example, by the late 1980s, shows hosted by Joan Rivers and Arsenio Hall helped late-night talk to become slightly less dominated by white males, while on Leno's program the studio band has been led by two Black musicians: the first leader was accomplished jazz musician Branford Marsalis; he has been followed by Kevin Eubanks.

     Another big change for The Tonight Show during Leno's tenure has been the program's first serious competition. Starting in the mid- to late 1980s, television talk shows, both daytime and late-night, multiplied in number. The in -studio talk program was inexpensive to produce. and audiences were increasingly drawn  to the sensationalism and celebrity  showcased each day and night on television. Some late-night talk shows - including those hosted by Joan Rivers, Chevy Chase, and Pat Sajak on the FOX network-came and went quickly. Popular comedian Arsenio Hall's late­ night talk show was on the air for several years before cancellation; for a time The Arsenio Hall Show had a wide following, attracting mostly a young black audience, a segment previously ignored in late-night talk Especially successful in late night was the up-and coming David Letterman. Late Night with David Letterman started out on NBC. airing immediately after The Tonight Show from 1982 until 1993. Passed over for the host position on The Tonight Show when Leno was chosen for the post, Letterman moved to CBS where his new show, The Late Show with David Letterman, has run in direct competition with Leno.

     Since the debut of The Late Show, Tire Tonight Show has for the first time had to share the late-night spotlight. The competing host/comedians, Leno and Letter­man, are polished performers with large audiences. They have become, as Carson had been, the gauge by which mainstream entertainment and politics are measured. On both programs comedy is delivered-and guests and issues of the day are treated in the same way, as gossip and light entertainment. The growing influence of both programs can also be measured by the influential guests each has featured. Political fig­ures such as Bill Clinton, Al Gore, George W. Bush, and New York City Mayor Rudolph Giuliani have all made appearances on the late-night programs to reach large audiences, thus enhancing the shows' cultural influence. After more than four decades, The Tonight Show still outlines and defines , even when it is not  at the forefront of, the essence of contemporary televised culture in the United States.