For me it's Nietzsche's "Thus spoke Zarathustra". I'm a different person each time I get through certain sections of that book. That said, I'm sure one of the h

For me it's Nietzsche's "Thus spoke Zarathustra". I'm a different person each time I get through certain sections of that book. That said, I'm sure one of the hundreds of unread books I own is equally life changing.