The stories of Steve Allen, Jack Paar and Johnny Carson headline this episode about the formative years of late-night television. Merv Griffin also emerges as a key player on the late-night scene. (His interview for Pioneers was his last before passing away.) Regis Philbin offers revelations about his years as a late-night sidekick (to Joey Bishop). Dick Cavett and Arsenio Hall also discuss their years in the mix, and Sigourney Weaver offers personal details about her father, Pat — the inventor of “Tonight.” The episode is peppered with dozens of never-before-seen clips, including Johnny Carson performing in his early 20s.