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.