In Mike Bullmore's excellent workshop at the Gospel Coalition, "The Functional Centrality of the Gospel," Mike commended to us a little book by Milton Vincent called A Gospel Primer for Christians: Learning to See the Glories of God's Love. Milton is a pastor in California. Mike's comments piqued my interests and I immediately ordered a used copy of the 90-page paperback from Amazon when I got home.
The book looks very good. The point of it is just what I've been discovering myself these days (don't know why it's taking me so long--though I expect in 40 years it will still feel like it's just beginning to sink in!) that the gospel is for believers, not just unbelievers. I had never heard of the book before Mike's recommendation but I look forward to diving in this week.