The Birth of Tragedy
It has been noted that Pirsig's romantic/classical dichotomy resembles Nietzsche's Dionysian/Apollonian dichotomy as described in "The Birth of Tragedy". For example, in his book "The Person of the Therapist", Edward Smith writes, "In his popular novel ... Pirsig also addressed the Apollonian and Dionysian worldviews, naming them respectively classical understanding and romantic understanding."