Here is my non-fiction library (actually, I only have a handful of fictional books anyway, and although I enjoyed all of them, I'm still not a big fan of fiction itself).
The categories of books my library falls into are Sermons, Christian Living, Church History (including biographies), Theology, and Apologetics.
Some of my favorite authors in my library are A.W. Tozer, A.W. Pink, C.S. Lewis, Ravi Zacharias, William Lane Craig, J.P. Moreland, Martin Luther & John Calvin, and especially the Puritans (such as Thomas Watson, Richard Baxter, and John Owen).
My most treasured books (after the Bible) are my five volume set of Charles Spurgeon's sermons (see bottom of photo). I highly recommend his sermons for Christ-centered preaching, both heart-warming encouragement and soul-distubring exhortation, biblical wisdom, and even for poetic beauty (some of his phrases are almost "Shakespearean" in the way Spurgeon preached).
Another sermon set I would recommend is G. Campbell Morgan's five volume set from his years at Westminster Chapel, England (that's the blue set of books in the photo in between the two Griffin book ends - and no, I do not believe in ancient creature mythology, my brother bought me those book ends!!!).
P.S. Please ignore the Chunks Ahoy cookie bag on my first shelf................. It came free with the shelf when I bought it (or if you don't believe that)............. that's the food I feed the Griffins, it's the only thing they'll eat (or if you don't believe that).................. okay I'm fresh out of excuses!!! I'm going to go eat a cookie!!!