Having seen it at least a few dozen times on Broadway, The show plays much better on its feet than on the page, after all don't most scripts?It's gothic darkness, and layered secrecy is very romantic and enthralling for an audience that is enticed by historical melo-drama. The show itself asks you to suspend reality. So no, not all of it is fact based. As it is based on a young adults novel, that should be an indication of the editing process it has undergone. It is a good read if you are a theater student or someone considering this show in their repertory. If you are considering reading it for the story, I would buy the young adult novel that the script was based on.