I missed Tim Keller last week in Pittsburgh and haven't read his book, but here's a talk he gave at Google in March:
The talk is interesting but he botches the Q&A. He must have expected a lot more flaming, because he was ready with a combative attitude. A few missteps:
He never really understood the first guy's question, which was a good one.
He introduces a questioner by saying, "Come on." Sounds like he meant "Bring it on!"
Using "you" is a defensive move--"What you are trying to do is ..."
He argues from authority: first the Bible (gets burned), then "Nicholas Wolterstorff's new book, Justice: Rights and Wrongs, it's brand new, it's a hard book, he's a philosopher from Yale, it's Princeton University Press ..." blah, blah, blah.
Makes a big deal out of Cornelius. He was supposed to roll with Cornelius.
The bottom line is that he's dealing with reeking geeks here. He's erudite but he's not a geek, so he comes across as a bit of a colonizing alien.