What is consciousness? Attempts to answer this question have motivated two interdisciplinary conferences sponsored by the University of Arizona in Tucson. This second volume presents a selection of invited papers from the second conference. The book's 15 sections demonstrate the broad range of fields now focusing on consciousness. The sections include philosophy, cognitive science, medicine, neurobiology, neural correlates, vision, sleep and dreaming, anaesthesia, molecular biology and evolution, quantum theory, spacetime, hierarchial organization and experimental approaches. Each section is preceded by an overview and commentary.