(Note this is cross-posted to the BaconMarathon blog)
If you are building an app for Facebook, good information can be hard to find. The Developer Docs do a decent job at getting you up to speed, but don't dive too deep.
A few of my favorite books at the moment are:
1. Facebook Application Development - most heavily used book in my collection. Solid examples, minimal errata.
2. Facebook Applications - Good sample app in the last third of the book that goes beyond simple implementation.
3. Facebook API Developers Guide - Great kick-starter, super quick read. Doesn't dive deep, but lays it out in a readily consumable fashion.
One overall issue - I haven't found a book that uses anything other than PHP. As we're using Java for our BaconMarathon apps, we've had to do a bit of "translation", but it hasn't slowed things down much.