Zen and the Art of Motorcycle Maintenance: An Inquiry into Values (ZAMM), first published in 1974, is a work of philosophical non-fiction, the first of Robert M. Pirsig's texts in which he explores his Metaphysics of Quality. The book sold 5 million copies worldwide. It was originally rejected by 121 publishers, more than any other bestselling book, according to the Guinness Book of Records. The title is an apparent play on the title of the book Zen in the Art of Archery by Eugen Herrigel. In its introduction, Pirsig explains that, despite its title, "it should in no way be associated with that great body of factual information relating to orthodox Zen Buddhist practice. It's not very factual on motorcycles, either." The book describes, in first person, a 17-day journey on his motorcycle from Minnesota to Northern California by the author (though he is not identified in the book) and his son Chris. They are joined for the first nine days of the trip by close friends John and Sylvia Sutherland, with whom they part ways in Montana. The trip is punctuated by numerous philosophical discussions, referred to as Chautauquas by the author, on topics including epistemology, ethical emotivism and the philosophy of science. Many of these discussions are tied together by the story of the narrator's own past self, who is referred to in the third person as Phaedrus (after Plato's dialogue). Phaedrus, a teacher of creative and technical writing at a small college, became engrossed in the question of what defines good writing, and what in general defines good, or "Quality". His philosophical investigations eventually drove him insane, and he was subjected to electroconvulsive therapy which permanently changed his personality. Towards the end of the book, Phaedrus's personality begins to re-emerge and the narrator is reconciled with his past.