I will assume that if you're here, you already know that those discs are a code. (When I found this out, I took a moment to make an offering to the gods of clockwork, steampunk, difference engines, for they are good to us. Also to Ada Lovelace, oft-forgotten programmer extraordinaire.) I'll also assume that you're having trouble cracking it. To that end, I've put together a few hints to help you out, because the reward really is intriguing.
My first hint is: STOP LOOKING FOR HINTS AND START SOLVING IT YOURSELF. SLACKER.
Seriously. Your self-esteem and your ego will thank me. This is a code that is meant to be broken (what good is it in this context otherwise?), so you know that it's not terribly difficult. Clever, yes. Difficult, no.
Ok, fine. We'll call that Hint 0. You won't be much happier with Hint 1, but here it is (last chance to do it yourself! Turn back now!) :
Look with your eyes.Courtesy of Arya Stark, via Syrio Forel, of course. Take a new look at the dust jacket. There are clues there to get you started - even clues to suggest the existence of a code, if you hadn't known there was one there. Look closely. Take it off the book, if you need to. The heart of codebreaking is in recognizing patterns where there don't seem to be any, so let your pattern-sensitive human brain take over for a minute, and go with your gut.
More hints to come. Enjoy!
Ready for more? Hint 2 is here.