What goes on in our heads when we have a thought? how do physical events that occur inside a fistful of gelatinous tissue give rise to a universe of conscious experience universe that contains everything we feel, everything we know, and everything we are? Scientists and philosophers have pondered these questions for more than two thousand years, but not until now has there been the possibility of answers grounded in scientific experiment. With this book, Edeman and Tononi present an empirically supported full-scale theory of consciousness. The theory provides for the first time a scientific understanding of the most general and fundamental properties of consciousness - the private and unitary nature of experience and yet the infinite variety of conscious states, stretching as widely as one's memory process might explain the generation of this fantastic number of unified conscious states -something far beyond the capabilities of present-day computers? To answer this question, the authors apply all of the resources and insights of modern neuroscience, from the largest computer models of the brain even constructed to new experiments that detect the changes in brain activity that occur when we are conscious or unconscious of a stimulus. Their arguments build on radical ideas earlier introduced by Nobel Laureate Gerald Edelman himself when he first applied Darwinian principles to the development of brain and mind. This pioneering work represents a landmark in our growing understanding of consciousness, perhaps the most exciting frontier of current science.