From time to time, I will review and/or list books that I find helpful.  I don’t have time to go into a full review while I’m on my lunch break, but right now I’m re-reading 
The Agile Samurai: How Agile Masters Deliver Great Software (Pragmatic Programmers), by Jonathan Rasmusson.  It’s a great back-to-basics book for those of us who have been doing the agile thing for a while.  For those of us who are newer to the agile universe, it is a must have for your Agile Library.  It also has some great tips and tricks for all role types.  I highly recommend it.  You can get the Kindle Edition for less than $20 on Amazon right now.