I just finished reading Seeing the Unseen by Joe Beam. It was an excellent book, and I would recommend it to anyone. If you would like to borrow it, let me know.
Beam spent many years traveling around and teaching about the subject-matter that became the book, and he provides a lot of insight into the invisible, spiritual forces, both good and evil, that are at work all around us. And while I agreed quite a bit, disagreed here and there, and found some of the information new and insightful, I was challenged the most by what seems to be the main premise of the book: that our battle against sin and the devil is better waged when we know it is going on–and when we know what is going on.
Satan works hard and is very good at what he does. He also has many soldiers to help him, human and otherwise. Yet, Christ works hard, and is even better at what He does. And He has a great army fighting with Him. The more I can learn about both sides, how one can harm me and the other help, sources of temptation and relief, how they interact with one another and with me, the better equipped I will be to serve God and win my battles.
A look into the unseen world revealed in the Bible educates and encourages me. I suggest you take a look as well.