Into the Unknown

A few years ago, I read a terrific collection of essays — It Must be Beautiful — on the great scientific equations of modern times. I loved it, but as I meandered through the book, I was struck by an unexpected poignancy. The first essays, by and large, described breakthroughs that had taken place in the laboratories of Europe. The second half was quite different. Some time in the 1920s, the balance of scientific discovery shifted inexorably to the U.S. A small book of essays held within it proof of a profound historical...