Im going through a book right now with my staff that is called "God doesn't believe in atheists. It was written in the early 90's by Ray Comfort. It is really good.
It is pretty much a debate against atheism and shows proof why God exists, and proof why atheist don't really exist. Now you might not know many people that are atheists but it is a great tool to give out to non believers that might have doubts if God exists. It is a quick read and he is very practical. Even if you are a believer, I think it could even help strengthen your faith, as it has done that for me.

If you don't know who he is, Ray Comfort is the British dude on TBN with Kirk Cameron.