Lee Smolin
The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next.
Houghton Mifflin, 392 pages, $26

Peter Woit
Not Even Wrong: The Failure of String Theory and the Search for Unity in Physical Law.
Basic Books, 291 pages, $26.95

For more than thirty years, string theory has been what Murray Gell-Mann called “the only game in town.” By this he meant that it was the only good candidate for a TOE, or Theory of Everything. Not only does it claim to unify relativity and quantum mechanics, it also explains the existence of all fundamental particles. Instead of being “pointlike,” they are modeled by filaments of energy so tiny that there is no known way to observe them or even to prove they are real.

A string can have two ends or be closed like a rubber band. Of great tensile strength, strings vibrate...