Developments in physics by 2005 led Hawking to revise the book. He enlisted as a collaborator Mlodinow, a fellow physicist and author, who had also written scripts for Star Trek: The Next Generation. The result was the critically acclaimed A Briefer History of Time, which not only updated the original book but also made the subject matter much more accessible.
Both books enticed readers with the same loose ends that drive theoretical physicists today: Quantum mechanics and general relativity, both remarkably successful in their qualitative and quantitative description of nature as well as their predictive power, do not mesh with each other at the subatomic level.
Because of that mismatch, physicists seek a Holy Grail, a so-called theory of everything that unites quantum theory and relativity. In their new book, Hawking and Mlodinow argue that such a theory, which they call the Grand Design, is now within reach.
Readers familiar with modern physics will find that claim both audacious and intriguing. They will open the book expecting a brief overview of Hawking's earlier work and then more detail about the mismatch between the two great theories. They will look for the authors to wade into the argument about the possibilities and limitations of string theory. (More about that below.) They will expect the book to point the way to a theory unlike any previously proposed.
But by the time they reach the end of Chapter 1 ("The Mystery of Being"), they will realize that The Grand Design is a very different kind of book. It is an odd hybrid that redefines science to include questions usually in the realm of philosophy and religion.
