Brave New World
The Complete Works of William Shakespeare
Tricky, yes, but Shakespeare does act as a guide for John. It is from Shakespeare (among other sources) that John gets his morality, his sense of value, his outlook on life, and his thoughts and opinions. Before Shakespeare, John had inklings as to his emotions, but it is after reading the plays that he can put words to them and can pair them with action. He gets the idea of killing Popé, after all, from reading Hamlet. That John uses a book as a mentor is a strong indication of just how isolated he's been from others for most of his life.