Brian Greene's The Elegant Universe is a beautiful book. A difficult book at times, but beautiful just the same. Greene is a good science writer in the sense that he balances narrative with explanation so that the reader feels they are in the grip of a story and at the same time are pushed to learn new ideas.<br><br>The focus of the book is, as the subtitle offers, the "Quest for the Ultimate Theory." Greene and many other physicists have for decades, even for centuries, been searching for a theory of the physical world that explains why everything is the way it is. Not just what is happening, both at the sub-microscopic and the hyper-macroscopic levels, but why it is happening, what exactly causes one thing to lead to another. They are, in effect, attempting to take the ground that has been held for the entire history of humanity by religion. The "why" of everything. Greene and his camp (and there certainly are opposing camps) are convinced that superstring theory is the most likely candidate for the ultimate theory. But like all good scientists, they hold close to their chests the caveat that another, bigger, more comprehensive theory might come along. It's an exciting journey, and Brian Greene has been an important player along the way. He speaks not just as an observer but as a key participant.<br><br>I confess to being lost in the concepts of quantum geometry, but I was enthralled with the possibilities of string theory to unite the findings of classical and quantum physics. I highly recommend the book to anyone interested in scientific theories of the ultimate, of attempts to understand everything from the beginning (and maybe even before the beginning) to the possible endings of the universe.