Quantum physics, evolution, computation, and knowledge--these four main strands of scientific theory and philosophy have, until now remained incomplete explanations of the way the universe works. These strands may seem unrelated, yet in "The Fabric of Reality" Oxford scholar David Deutsch shows that they are so closely intertwined that we cannot properly understand any one of them without reference to the other three. Considered jointly, they reveal a unifed fabric of reality that is objective and comprehensible, and in which human actions and ideas play essential roles.