That's how mathematician Peter Woit of Columbia University describes string theory. In his book, "Not Even Wrong," published in the U.K. this month and due in the U.S. in September, he calls the theory "a disaster for physics."

A year or two ago, that would have been a fringe opinion, motivated by sour grapes over not sitting at physics' equivalent of the cool kids' table. But now, after two decades in which string theory has been the doyenne of best-seller lists and the dominant paradigm in particle physics, Mr. Woit has company.

"When it comes to extending our knowledge of the laws of nature, we have made no real headway" in 30 years, writes physicist Lee Smolin of the Perimeter Institute in Waterloo, Canada, in his book, "The Trouble with Physics," also due in September. "It's called hitting the wall."

He blames string theory for this "crisis in particle physics," the branch of physics that tries to explain the most fundamental forces and building blocks of the world.