David Kaiser is the Germeshausen Professor of the History of Science and professor of physics at the Massachusetts Institute of Technology. He is the author of Drawing Theories Apart, also published by the University of Chicago Press, and How the Hippies Saved Physics. He lives near Boston, Massachusetts. W. Patrick McCray is professor in the department of history at the University of California, Santa Barbara. He is the author of The Visioneers and Keep Watching the Skies. He lives in Santa Barbara, California.