This article was adapted by Gary Taubes from an article written by MIT scientist Daniel Kleppner for Beyond Discovery TM: The Path from Research to Human Benefit, a project of the National Academy of Sciences. The Academy, located in Washington, D.C., is a society of distinguished scholars engaged in scientific and engineering research and dedicated to the use of science and technology for the public welfare. For more than a century, it has provided independent, objective scientific advice to the nation.