I approach today’s topic in Resources for Thinking Christianly with some trepidation. It’s about reading good books. There is problem with that: there are so many of them!

So let’s cut the topic down to size by talking about good books, not-so-good books, and how to tell the difference. The not-so-good ones far outnumber the worthwhile ones. If thinking Christianly is your objective, you can certainly go wrong, even with books from the Christian bookstore. I’m thinking of a book I was reading just this week that tries rather too hard to count Isaac Newton as an orthodox Christian, and Thomas Jefferson as one who respected the Christ of the Bible. Even more common than factually flawed books like that, however, are books that are fail to engage real thinking. Squishy books, I call them. They’re not just at Borders and Barnes & Noble; they’re also at Family, Berean, and LifeWay.

How then do you know what’s a good book? I could list my ten favorites, but that wouldn’t get you very far. Instead I’m going to suggest how to go about looking for them.

1. Rely on good reviews from good sources—Books and Culture, First Things, and Touchstone, among others. Tim Challies is the one Christian blogger I would most recommend as a book reviewer; in addition to his blog, he edits The Discerning Reader. I’ve done a few reviews myself.

2. Read old books. One of C.S. Lewis’s most famous words of advice was,

“It is a good rule, after reading a new book, never to allow yourself another new one till you have read an old one in between. If that is too much for you, you should at least read one old one to every three new ones.

Every age has its own outlook. It is specially good at seeing certain truths and specially liable to make certain mistakes. We all, therefore, need the books that will correct the characteristic mistakes of our own period. And that means the old books.”

A further virtue of old books is that time weeds out the weak ones. Old books are likely to be good books.

3. Read challenging books. I have nothing against reading for information or entertainment, and I like a Grisham novel as well as anyone; but I grow most when I work hardest. Read material that stretches you. Don’t be afraid to get help with it; that’s perfectly fine. Cliff’s Notes and SparkNotes were off limits for most of us in high school and college—too many students use them as shortcuts. That’s not what you’re doing now, though. They may be just the thing to get you through some difficult classic material you’re working through.

4. Read all kinds of books. For heaven’s sake, don’t think you must limit yourself to Christian non-fiction. Balance your diet. Dostoyevski and Shakespeare may grow you just as much, both mentally and spiritually, as C.S. Lewis or John Piper. Poetry can put you in touch with beauty as almost no other writing can. Biography, nature, history, leadership studies … I could go on and on.

5. Read other perspectives. Today I finished a book by two gay authors on strategy for the homosexual rights movement. Do you think there was no growth for me in encountering their point of view? They are, first of all, two human beings, with a particular human perspective on life. If I as a Christian cannot listen to their perspective, how can I speak God’s truth to them in love? Or, if I do not try to understand naturalism or atheism, could I pretend know what to think about those topics? If my Christianity cannot stand up to differing opinions, then how can I be confident in it? Paul demonstrated knowledge of secular authors, especially in Acts 17.

There is indeed much to read. I love bookstores and I hate them: I want to read everything, and I’m frustrated knowing how much I will never have time for. Do you see why it’s so important to choose our reading wisely? But be encouraged: you don’t have to do this all at once. It’s a lifetime pursuit.

Be encouraged, too, that not every book must be read deeply. I had a class with the late missiologist Dr. Ralph Winter, who advised us, “Don’t read—ransack!” He was referring to a particular kind of reading: for research or for specific information. It’s great advice, though not for all kinds of material: poetry, say, or an extended philosophical treatise. I’ve even used the ransack technique in the Bible—looking for places where Jesus spoke his purpose, for example.

Speaking of the Bible, have you noticed how uniquely it fits the criteria I’ve listed above? It’s challenging; it’s time-tested (a very good book!); it includes biography, history, poetry, theology, philosophy, and more. And if you think it won’t test and change your perspective on life—even as a Christian—then I would say you haven’t been looking into it deeply enough!