Vern Poythress wrote In the Beginning Was the Word: Language—A God Centered Approach (Wheaton, IL: Crossway Books, 2009). Not the easiest read but well worth the effort. Demonstrates how we cannot have communication without objective propositions. Not the easiest read for most, but excellent work. Recommended.
Philosophy
The End of Reason
Ravi Zacharias, Ph.D., The End of Reason, is a short work by a very fine Christian apologist; easy reading. Highly recommended.
Alistair Kee, Nietzsche against the Crucified
Alistair Kee, Nietzsche Against the Crucified. This is an analysis of the philosophy of Nietzsche by a non-Christian. Very insightful and helpful into Nietzsche’s dark thought.
Thomas Cathcart and Daniel Klein, Plato and a Platypus Walk into a Bar
Thomas Cathcart and Daniel Klein, Plato and a Platypus Walk into a Bar . . . This is a humorous and easy to understand introduction to philosophy. Short read.
Nietzsche
Friedrich Nietzsche, Joyful Wisdom. Difficult reading at times, and convoluted, but if one wants to read him first hand, this is one of his more popular works.