"It is a search for a view of the universe that unites two seemingly opposed pillars of modern science: Einstein's theory of general relativity, which deals with large scale phenomena like planets, solar systems and galaxies, and quantum theory, which deals with the world of the very small - molecules, atoms and electrons. In the last few years, physicists have made big steps toward their goal of a completely new theory of space, time and the universe, a "theory of everything. " In Three Roads to Quantum Gravity, Lee Smolin, who has spent his career at the forefront of these new discoveries, presents the main ideas behind the new developments that have brought a quantum theory of gravity in sight. He explains in simple terms what scientists are talking about when they say the world is made from exotic entities such as loops, strings and black holes. As he does so, he tells the stories behind these discoveries: the rivalries, epiphanies and intrigues he witnessed first hand. "--BOOK JACKET.