But if you don't know what canon is, how can you be sure what canon isn't?
I think books are what you can consider loose canon, just like games (after all, the games weren't 100% linear and you could make some major decisions).
The basis and most important events are true, but some minor plot twists are open to interpretation in different ways.
I think it's safe to say the books are canon until another canon source says otherwise.
Then it's open to interpretation.
