Paul Reubens never got to be on 'The Tonight Show' with Johnny Carson and wondered why.

The book 'Love Johnny Carson' says Paul Reubens wasn't invited because he only appeared as Pee-Wee Herman at the time.

Johnny Carson didn't want guests who might confuse the audience. He made exceptions for obvious characters like Super Dave Osborne.

Carson only invited people who were clearly pretending to be someone else, like Father Guido Sarducci.

Paul Reubens wasn't invited to 'The Tonight Show' because he wanted to appear as Pee-Wee Herman.

A book about Johnny Carson reveals a 'ban list' for 'The Tonight Show' featuring Jay Leno and Ellen DeGeneres.

Carson had a rule from the start: no guests who might be pretending. He thought Bob Uecker was a comedian pretending to be a baseball player.

Carson wondered if singer Tiny Tim was real or pretending. He figured it out by the end of Tiny Tim's first appearance.

Tiny Tim got married on Carson's show, and 40 million people watched.

Paul Reubens appeared on 'The Tonight Show' when Joan Rivers was the guest host.

In 1985, Reubens was a guest on a Halloween episode of 'The Tonight Show' with Joan Rivers as host.

Reubens also appeared on Rivers' talk show two years later. His humor appealed to her younger audience.

Paul Reubens was a guest on Joan Rivers' show.

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Many celebrities were on the 'Tonight Show' ban list.

According to the book, Ellen DeGeneres, Jay Leno, and William Shatner were barred from the show.

Jay Leno appeared on the show several times before getting banned after his fifth appearance in 1978.

The audience didn't laugh much at Leno's jokes, so Carson decided not to invite him back.

A talent scout tried to fight for Leno, but the producer shut him down.

Peter Lassally said Carson didn't like Leno or his jokes, and that wouldn't change.

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Jay Leno was on the ban list but later hosted 'The Tonight Show' for 22 years.

Leno hosted 'The Tonight Show' from 1992 to 2009 and again from 2010 to 2014.

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