What to read after Zen and the Art of Motorcycle Maintenance?

"The real cycle you're working on is a cycle called 'yourself.' This book is an autobiography of the mind and body. It is a narration of a motorcycle trip taken by a father and his eleven-year-old son; a summer junket that confronts mortal truths on the journey of life. As the miles pass, the mind expands, and the narrator's tale covers many topics, from motorcycle maintenance itself through a search for how to live, an inquiry into 'what is best, ' and the creation of a philosophical system reconciling science, religion, and humanism. Unwanted and unbidden is the narrator's confrontation with a ghost: his former self, a brilliant man whose search for truth drove him to madness and death. This ghost, Phaedrus, haunts the narrator as he and his son visit places where they once lived. And, too, he confronts his deteriorating relationship with his son, who has himself been diagnosed as suffering the beginning symptoms of metal illness."--Publisher description.