Johnny Carson deftly navigates the turbulent 1960s to elevate The Tonight Show into a cultural touchstone, enshrining himself as the undisputed king of late night. His success begets competition with the emergence of Dick Cavett and Merv Griffin.

As the 1980s dawn, David Letterman reinvents late night comedy for a new generation, rescuing comedian Jay Leno's nearly flamed-out career in the process. But Johnny Carson's enduring comic appeal spawns endless speculation over his eventual successor.

Carson's 1992 retirement touches a nation – and touches off an epic late-night war between Jay Leno and David Letterman.