What could quantum mechanics have in common with the philosophical musings of the ancient Greeks? French physicists Etienne Klein and Marc Lachieze-Rey see an unbroken thread running from antiquity to the present - an ongoing search, throughout the history of science, for unity. In The Search for Unity the authors reveal how the quest for the One has driven all the great breakthroughs in science. They show how the Greeks searched for the fundamental element in all things; how Galileo unified the earth with the heavens, by discovering valleys and mountains on the moon; and how Newton created a single theory to describe the motion of the celestial bodies. Throughout the book, the authors stress the esthetic motives of scientists, how they recognize truth through apprehension of mathematical beauty. And in tracing the quest for unity up to the present day, they illuminate the bizarre workings of quantum mechanics and the sticky definition of reality itself at the subatomic level.