I recently received and read Ascent from Darkness by Michael Leehan. It's a personal account of a man who was a self-proclaimed soldier for Satan and how he was released from that by the power of God.
As a regular reader, it's an interesting read. Some of Leehan's experiences are vivid -- to the point of not being sure if I wanted to continue reading (especially seeing as how I usually read before bed lol).
As a Christian, I forced myself to continue reading because I think it's important for us to know (or hopefully, to remind) ourselves of the spiritual warfare that is constantly surrounding us and how subtle and sneaky evil is. The Bible talks about knowing your enemy and through this book, one is able to deconstruct the ploys of evil and know how he works and operates.
What just came to mind is the Scripture in Gen 50:20....
You intended to harm me, but God intended it all for good. He brought me to this position so I could save the lives of many people. Through Leehan's experience and situation and subsequent book, many people are helped.
I would definitely suggest this book, but really only for a mature Christian.