The Afterword illustrates the operation of the exchange order by analogy to Braudel’s division of history into three frames and considers how this order might best be studied. Markets, tort, and criminal liability each operate at three levels of depth: a surface level where individual transactions are carried out and change is rapid, a middle level where the forces that determine costs and prices and the patterns of exchange interact and change is slower but discernible, and a deepest level that represents the fundamental commitment of the system to the social function of exchange governance, which changes very slowly, if at all. Nothing in any of these systems is ever in equilibrium, and the optimizing methods of Pigovian economics are not as useful in understanding how they work and change as are the historical, comparative methods of evolutionary biology.