text: Carson also frequently used guest hosts, especially after 1981 when he negotiated a contract that gave him numerous weeks off every year, as well as Mondays.  Frequent guest hosts (over 50 episodes each) included Joey Bishop (177 times, mostly in the 1960s), Joan Rivers (93, during the 1970s and 1980s), John Davidson (87), Bob Newhart (87), David Brenner (70), McLean Stevenson (58), Jerry Lewis (52, mostly in the 1960s), David Letterman (51, mostly between 1980 and 1981), and Jay Leno.  By the late 1980s, Leno was designated the permanent and only guest host, and consequently hosted several dozen episodes each year, totalling 333 "guest host" appearances during Carson's tenure.
  Jay Leno (1992–2009)
  On May 22, 1992, Johnny Carson retired after three decades behind the iconic late-night desk, and was replaced by Jay Leno amid national and media controversy. David Letterman not only wanted to move into that earlier time slot from his Late Night spot (which had been broadcast following Carson's program) after The Tonight Show, and was considered personally by Carson (whose opinion was not revealed until several years later) as his natural successor despite Leno having been Carson's permanent guest host for several years. Letterman, having had his heart set on the earlier time slot in spite of Leno's ratings success as recurring substitute host, left NBC (on Carson's advice) and joined rival network CBS. Their new program and entry into the late-night television universe, Late Show with David Letterman, airing in the same slot, competed head to head against The Tonight Show with Leno in the host's chair and behind that iconic desk, for the better part of two decades, although Leno consistently enjoyed higher ratings after the first two years.