As a C-K player, I've come more and more to enjoy the Slav vs. d4. I'm still only a babe in the woods with this opening, though. What book(s) or other resources would people suggest for someone like me trying to build a repertoire that includes the Slav?

Also, on the same topic, I've put together a little one round tournament for people who want to practice the Slav. Click here for more info.

Play the Slav by Vigus and Starting Out: Slav and Semi-Slav by Flear were both useful to me.  The former offers a repertoire for black while the latter is a review of the main lines.