Good question. In the revised edition, he does mention his son, Chris, being murdered, a few years after ZAMM was published. I'd like to think that the trip itself was actually true, but perhaps some of the dialogue was created for some of his philosophical discussions. I even remember in the book that he and Chris stopped over at a colleague's house one evening and he went into some kind of philosophical monologue in front of them. Is that crazy? I don't know. I have had professors in the past that would do that. I don't think Pirsig was crazy, maybe having problems, and trying to grasp them and grasp his life too. Anyway, that's the best I can offer.