At its best, then, missional thinking is about helping the saints share the good news and love their neighbors; at worst it is the insecure immigrant kid who wants to be mainstream. Keller, as I say, is its best. Yet in all its varieties, missional thinking treats the church’s greatest challenge as knowing how to establish an interface with the world in order to reach the world. The book does not say this, but I believe that this is the primary problem that Center Church’s paradigmatic church is trying to solve: how can we reach the world? That is the revivalist in Keller (a label he seems to own), and, as I will suggest in a moment, many of the answers he gives to this question are good.