This article gives a good sense of the Larry Summers that I know—particularly how much he loves a good intellectual discussion from almost any starting point. Having Larry as one of my professors in graduate school and watching him during breaks at conferences gave me the view (which I still hold), that the most important economics is what happens in the hallways on those breaks (and often beyond, as those in a good discussion play hooky from the next formal talk). I draw from that premise the conclusion that the purpose of economic models is to train our intuition so that we are well prepared for such free-wheeling discussions.