Along with Caltech physicist Mlodinow (The Drunkard's Walk), University of Cambridge cosmologist Hawking (A Brief History of Time) deftly mixes cutting-edge physics to answer three key questions: Why is there something rather than nothing? Why do we exist? Why this particular set of laws and not some other?-- and explains that scientists are approaching what is called "M-theory," a collection of overlapping theories (including string theory) that...

Using humor, everyday examples and computer animation for the more abstract concepts, author and physicist Brian Greene explains complex theories of the universe and the focus of his research, string theory.