It's always been in the back of my mind to read the Star Wars books after Disney came out and said that they are no longer considered canon. I've been able to get my hands on most of the books. I just read through the Darth Bane series, but I found I was left with one question. Any time I bring it up to my Star Wars nerd friends, all I ever get is a funny look and shrugged shoulders.

(If you haven't read the Darth Bane series, spoiler alert)

In the first book, it ends with Bane bringing about the destruction of the Sith Brotherhood of Darkness. Great! He has found an apprentice, teaches her about the Rule of Two, and the Jedi think the Sith are extinct. In the second book, the Jedi are told that a Sith Lord survived, and they kill the wrong man. Again, the Jedi think the Sith are extinct. Final book sees the conclusion of the Rule of Two when Zannah becomes the Dark Lord.

So they make it clear that the Jedi believe the Sith are destroyed, and when they kill the wrong person, they aren't aware of Zannah as a second Darth. Now, let's fast forward 1000 years to the time of Episode I. Yes, we all know there are many problems with the prequels, but bear with me. At the end of the movie, Yoda is talking with Windu about Darth Maul. Yoda says something that, when taken with the context of the Bane series, doesn't make sense.

"Always two there are, a master and an apprentice."

If the book was considered canon, how can it make sense for the Jedi to know about the base principle of the Rule of Two?

Well, even earlier in the movie the Jedi make comments indicating they believe the sith to be extinct.

I have sort of reconciled that as, in between Maul fighting Qui-Gon on tatooine and the end of the movie, the Jedi council have conducted a series of deep meditations into the force in order to divine to truth surrounding Qui-Gon's attacker, and those meditations have led them to the discovering that the sith have returned and the rule of two (which I always thought was a really lame thing to imagine was codified into some formal rule).

I figure this technique was also used to determine that Dooku was actually telling the truth when he told obi-wan that a Sith Lord had control of the senate, even though they didn't believe him at first (and how bloody blind do you have to be to not be able to figure out who it is, once you accept that someone is, in fact, manipulating the senate. Sheesh.)

Movies override books if there's a contradiction, so the books are incorrect. Presumably the Jedi learned about the Rule of Two at some point, although they do seem to go into Episode I thinking the Sith are gone either way.

Just had to read the next book that is chronological to the time line. Plagueis describes how a sith lord fell to the light. Haven't finished the book, so don't know if he went full jedi, but at least it adds up now.