From Rick Warren, “The Battle for Your Mind” in Thinking. Loving. Doing. A Call to Glorify God with Heart and Mind, ed. John Piper and David Mathis (Wheaton, IL: Crossway, 2011), 34:

If you’re serious about growing in knowledge and growing in your mind, here’s the approach I suggest:

• Read 25 percent of your books from the first fifteen hundred years of church history. So many people act like nothing happened between the times of Paul and Luther. God was at work all that time, and we are dismissing the God of the church to think that he was not having his Word faithfully taught during these times.
• Read 25 percent from the last five hundred years, since the Reformation.
• Read 25 percent from the last one hundred years.
• Read only 25 percent from contemporary authors of the last ten years.