Mr. B is Bob's Obi-wan. He's his Morpheus. He's that dad that somehow never gets mentioned throughout the whole novel. We get the feeling that if Bob ever listened to Mr. B he might turn out to be a well-adjusted young man, but that's not happening anytime soon. Without Mr. B, Bob is so hopeless that he can't even figure out how to get a ticket to the zoo. That is pretty sad. So, even though Bob doesn't ever listen, Mr. B is totally Bob's mentor.