I've recently finished reading Clement of Alexandria 's Second book of his three books of the Instructor. I also just finished C.S. Lewis' The Problem With Pain. Though I was wonderfully impressed with the first book that I read by St. Clement's, Exhortation to the Heathen, I've not found the first two books of the Instructor to be all that great. There is much good advice in them and a good bit of legalism as well.
Lewis' The Problem With Pain was not at all what I expected. I thought it would be about his personal dealings with pain, but this is not what it is about at all. It's a book about how and why pain exists in this world that is created by God, who is perfectly good. Much of it is very good, some of it is purely speculative, but at these points Lewis usually tells you when he is speculating. Still his speculations are often insightful and always interesting.
With that said I have to disagree with Lewis on several instances. He is clearly opposed to Calvinism, but what he writes in this book on the Calvinist teaching of "total depravity" shows that he has not taken the time to understand what Calvinists truly believe when they use that phrase.
As a firmly planted creationist, I also find Lewis' ready acceptance of biological evolution to be a weakness in his thought. There were other things that I believe to be deficient in the book, but it is still a book that will cause you to think about serious issues and Lewis has insights that are, at times, amazing. It is, like everything else that I've read by C.S. Lewis, worth reading, especially if you are interested in thinking and being challenged.