Brennan Manning, yet.

From CCM magazine (hat tip to @U2): Philip Yancey of Christianity Today (whose What's So Amazing About Grace Bono is said to pass around to friends) telling a story about U2 meeting with Brennan Manning. (It never ceases to amaze me who they read. Years ago, by the way, I was one of the musicians at a service with Brennan Manning!) The story also makes clear that Yancey has gotten to know U2 himself by now. Yancey relates that The Edge asked Manning "Can I glorify God by being the best rock guitarist I can be?" and, of course, Manning said yes. (My personal theory: U2 answered such questions years ago and this was more a test of Manning than a request for information. But maybe not.)

Manning is probably best known for The Ragamuffin Gospel, but he has written a lot of books: Abba's Child, The Signature of Jesus, and so on -- just look around Amazon a bit. And (as with Yancey's catalogue) it's easy to see why his material would connect well with some of U2's artistic preoccupations.

{Update: By the way, it occurs to me many people may never have read the Rattle & Hum-era interview with Edge in CCM magazine, so I thought I'd link it while we were talking about CCM.}