"Baker's Encyclopedia of Chrisitian Apologetics" by Norman L Geisler. Apologetics (not apologetic or apologizing because of an error, it is a branch of study devoted to the defense of the faith). Geisler has an amazing way of putting things into words and writing with a lot of simplicity and helpful charts. If you are interested in finding answers to perplexing questions about the Christian faith then this is a book you may want to consult. Also he writes about some of the men that have been most influential in the medieval and modern Christian era. 1 Volume, and 841 pages of good stuff no doubt. Since the prolifiration of books on CD-DVD, Geisler's complete work on Apologetics is also available somewhere out there in cyberspace or your nearest "Christian" Bookstore. That one contains a boat load of his other writings - but that is beyond the scope of this blog thread.