There are a number of books on various topics that are quite good. These are the sort of books that it would be worth your money to actually buy.
The first book is Real Essentialism. This is a book that explains the philosophy of Thomas Aquinas for the modern reader. It defends Aristotelian philosophy (basic to Aquinas’ beliefs) in the context of modern biology, chemistry and physics. Although I do not agree with every point in this work, many of them are valuable. Even the mistakes are something that you can learn from.
The second book is Christian America?: What Evangelicals Really Want. This is a sociological analysis by university professors. They accurately determine what the average evangelical in America really believes and acts like. Topics include views on politics, marriage and the family, education and other religions. From my reading I can tell that this book is by far the most accurate analysis of American evangelicals that I have ever read.
The third book is Aristotle’s Topics. It contains an excellent commentary on Aristotle’s Topics. This book explains how to argue properly and how to use arguments to find the truth. The commentary and analysis of that book is quite good. From my reading of it, I can tell that it is accurate and quite comprehensive.
The fourth book is Aristotle’s De Anima. This is Aristotle’s work on the soul – living things. It contains his argument that the soul is immortal, his understanding of perception and knowledge and the difference between the various capacities of the soul. The analysis is the best I have ever read and explains Aristotle in a way that lets you appreciate what he said without having to know Greek.
The final book is Laws in Nature. This book is written by a modern philosophy who argues that Natural Laws (such as the law of gravity) do not exist. He accepts the patterns in nature that the ‘laws’ talk about, but denies that they are laws. His arguments and understanding can be easily understood from within an Aristotelian framework. I am aware of no book quite like this one. While I would have preferred it if more attention was paid to Aristotelian philosophy, the book manages to defend its thesis very well.