Is consciousness nothing more than brain tissue, as Daniel Dennett argues in his best-selling Consciousness Explained? Or, as others claim, is it a fundamental reality like space, time, and matter? In recent years the nature of consciousness—our immediately known experiences—has taken its place as the most profound problem that science faces. Now in this brilliant and thoroughly accessible new book Colin McGinn takes a provocative position on this perplexing problem. Arguing that we can never truly “know” consciousness—that the human intellect is simply not equipped to unravel this mystery—he demonstrates that accepting this limitation in fact opens up a whole new field of investigation. Indeed, he asserts, consciousness is the best place from which to begin to understand the internal make-up of human intelligence, to investigate our cognitive strengths and weaknesses, and to explore the possibility of machine minds. In elegant prose, McGinn explores the implications of this Mysterian position—such as the new value it gives to the power of dreams and of introspection—and challenges the reader with intriguing questions about the very nature of our minds and brains.