As it happens, I have been a runner and a serious track-and-field fan my entire life, and I have never seen a boy who was slow become fast either. For that matter, I’ve never met someone who thinks a boy who was slow can become fast. Epstein has written a wonderful book. But I wonder if, in his zeal to stake out a provocative claim on this one matter, he has built himself a straw man. The point of Simon and Chase’s paper years ago was that cognitively complex activities take many years to master because they require that a very long list of situations and possibilities and scenarios be experienced and processed. There’s a reason the Beatles didn’t give us “The White Album” when they were teen-agers. And if the surgeon who wants to fuse your spinal cord did some newfangled online accelerated residency, you should probably tell him no. It does not invalidate the ten-thousand-hour principle, however, to point out that in instances where there are not a long list of situations and scenarios and possibilities to master—like jumping really high, running as fast as you can in a straight line, or directing a sharp object at a large, round piece of cork—expertise can be attained a whole lot more quickly. What Simon and Chase wrote forty years ago remains true today. In cognitively demanding fields, there are no naturals.