I asked the question because, on the movie side, I was wondering a while ago why Michael designated Clemenza as the one who should hide the gun for him.

In the book, the narrative of Vito's life says that, when he appointed Tessio and Clemenza as capos, he told them not to associate with each other, even socially. Tessio operated largely indepndently, while Clemenza was kept in the Don's chain of command.

I wonder how far that went. There is not even mention of Tessio at the wedding, but from his childhood Mike remembers Clemenza as someone who would take him somewhere when the Don was too busy. I think that had a lot to do with why Michael chose Clemenza -- he just knew and trusted him.

Tessio first enters the story when he is called by Sonny after Vito is shot. Some of the language in the conversation is pretty interesting (I don't have the book in front of me, so I'll paraphrase). At one point, Sonny tells Tessio about "My kid brother Mike", and he tells Tessio that Mike is in college in Hanover, New Hampshire. That's not the sort of detail that you usually have to give someone who's known and done business with your family for thirty years, especially considering that Mike had made a big stir at the wedding just a couple of months before.

Also, when they arrange for Tessio to send men to guard the Don and the mall, Tessio ends the exchange by asking, "You know my boys, right?" Sonny says sure, but again it seems like these guys aren't completely familiarized with each other.

I tend to be on Vito's side in the great Vito/Michael debate, but in this instance, I think that Vito made a mistake by keeping Tessio's regime so isolated from the rest of the family. I think that a lot of trouble somehow could have been avoided, if Vito had just invited Tessio to the wedding.