Ray Richmond is contributing to Deadline’s coverage of TCA.

How come we never see any clips from Johnny Carson’s Tonight Show during that show’s first decade (1962-72)? Why was Carson essentially missing in action over the last 13 years of his life that ended on January 23, 2005? Some answers were provided this morning during a TCA panel promoting the PBS American Masters doc Johnny Carson: King of Late Night, scheduled to premiere May 14. The doc’s writer-producer-director Peter Jones confirmed that he had been pursuing Carson in letters from the time he famously retired from Tonight in 1992 to participate in a doc on his life, but he never received so much as a response. “Then one day in 2002 I got a call and heard, ‘Johnny Carson’s on Line 2,’ and I thought it was a joke. But it was really Johnny. He said to me, ‘Peter, you write a very good letter. I know you want me to participate in this, but I won’t be doing anything about my life because you know what? I don’t give a shit. … I’ve done everything I want to do and said everything I want to say. There is nothing more.’ And that was that.” As for why there is rarely a clip to be found from Tonight‘s early years with Carson, Jones noted that NBC routinely recorded over the previous night’s edition of the show because “video was so expensive back then. They cost $500 apiece. Consequently, the first 10 years of the show virtually do not exist. You only find them now in kinescopes that fans and collectors made. … It was one reason why Johnny stipulated ownership of the show retroactively.”

Jones, joined on the TCA panel by regular Carson guest Angie Dickinson and comedian Drew Carey — who famously was invited to join Johnny on the couch following his first appearance on Tonight — found enthusiastic participation in the doc from Hollywood. Only two celebs who were asked declined to participate: Woody Allen and Bill Cosby. Jones declined to elaborate why. But surprisingly, one personality who did agree to be interviewed was Joan Rivers, whose joining Fox to host her own competing (short-lived) late-night talk show in the late 1980s spurred her complete estrangement from Carson. “Joan really speaks about that for the first time with us,” Jones said. “She admits that she probably shouldn’t have let Johnny find out about it second-hand. … Johnny never spoke with Joan again. She called him to discuss it with him and he hung up on her. The whole thing with Joan broke Jobhnny’s heart, it really did.” Of Carson’s four wives, only second wife Joanne agreed to be interviewed on camera. “The others,” said Jones, “worried that Johnny was still looking over their shoulder.”