If you're interested in philosophy, pseudoscience, intelligent design creationism, the nature of science and the supernatural, methodological naturalism and so on, then I'd recommend adding Maarten Boudry's Here be dragons to your library. If your the type that spends time arguing with the religious or followers of intelligent design, then this book could help polish your own arguments and understanding of the issues from a philosophical perspective.
It's a 287-page collaborative PhD thesis, and well worth a read.
Direct link to pdf (2.8 MB): Here be dragons - Exploring the hinterland of science by Maarten Boudry
The book is free and legal to download, so need to worry about illegally downloading copyrighted material.