Did Joan Rivers' husband cause her infamous breach with Johnny Carson?

Johnny Carson's former lawyer, Henry Bushkin, has written a book on his onetime friend and boss (who died in 2005), which was published Tuesday and embargoed by the publisher until that date, though certainly some details have already leaked out:

Probably the biggest, I suppose: That Carson had tried to hit on a mobster's girlfriend (a so-called "goomah .?.?." ) and then the mobster tried to hit on Johnny. Of course, impossible to confirm, but that's the story. (Bushkin -- the "Bombastic Bushkin" -- and Carson had a bitter falling out many years ago.)

But from my perspective, this is more interesting: Was Joan Rivers' husband, Edgar Rosenberg, who committed suicide in 1987, the direct cause of Carson's breach with her? Bushkin says as much in his book, which is intriguing because Rivers'  break with Carson is one of the most famous stories in late night TV  history.

She had been, as you may be aware, Carson's chief stand-in at "Tonight" which had helped establish her heir-apparent credentials there (though per Bushkin, she was never on NBC's short list of possible replacements). Unknown to Carson, she then went to Fox to become host of an 11 p.m. show there (the network's first regularly scheduled series). Carson felt betrayed, and  was betrayed, and she was henceforth banned from his orbit. Her show was canceled after a few months, and Rivers never fully recovered, at least professionally, after the Carson banishment.

But .?.?. was the whole thing a misunderstanding? Rivers has long maintained that it was, but Bushkin brings up this: That her husband Edgar had lied to her about trying to reach out to Carson before the Fox show was announced. Per Bushkin, Rosenberg -- who was doubling as Rivers' exec producer at Fox -- had said he had tried to repeatedly call the lawyer, while Bushkin insists that no calls had ever come in.

He writes: "To me, it's entirely plausible Edgar feared that if Johnny talked to Joan and offered her an inducement in any way -- a free oil change at Jiffy Lube, say -- she would have rejected Fox and stayed with 'The Tonight Show.'"

Bushkin insists Carson would have not stood in her way.

Any of this true? Impossible, of course, to confirm.

Bushkin and Carson had a famed falling out as well -- over a soured business deal. Carson would never forgive Bushkin, and certainly some will argue that Bushkin -- like Rivers -- never fully recovered  from the Carson freeze-out and that this book is payback. True or not, the book does contain interesting details, and I'll keep mining 'em for TV Zone readers.