This book is the BEST book I have ever read on spiritual warfare (SW). That is, it is the best book I've read the covers the "practicalities" of the process (and processes) of SW. That said, the primary function of SW is to KNOW your enemy (or as the old saying goes "information is POWER"). And this book gives you A LOT of information and/or many of the facets of the powerful being (and his dominion) known as Satan (or the Devil). Warren Wiersbe does not write like other authors on the topic of SW - thus, he doesn't regurgitate the same information over-and-over again. Wiersbe gets Straight-to-the-point!!, and doesn't fool around with extra-biblical conjecture or fantasy, as many other "Christian" (so-called) writers today. So I would HIGHLY recommend this book. It is NOT the Holy Bible, but it is indeed an very nice supplement to the concepts about SW, Satan, and his evil army. The only difficult part is DOING/Following the advice given from/in the book (as it is always hard to put to "practice" the things of the spirit/spiritual - that is why you cannot do them unless [or until] you pray and call for help from the Holy Spirit [God] Himself - take it for what its worth). Lastly, I must warn anyone who does begin to read this book, that you WILL begin to experience resistance and attacks from the one in which this book is written about. So I am almost certain you will find out, first hand, who Satan is, as he will send all types of distractions, trials, etc., in order for you not to completely grasp or understand what is written. So WATCH OUT!
If your looking for a book that understands the meaning of the angelic conflict, and the invisible but real happenings that matter in this world we live in, then this is one for your book self. An excellent read with scripture based material, what I call "priceless". The Armor of God needs to be worn and ready at all times, Wiersbe shows you why this is true. Also, the importance of knowing what the enemy tries to do and will acheive against all believers, if not prepared. High recommendation for more then a one time read, keep for reference.