Book excerpt: “A first-class intellectual adventure.” —Brian Greene, author of Until the End of Time Illuminating his groundbreaking theory of consciousness, known as the attention schema theory, Michael S. A. Graziano traces the evolution of the mind over millions of years, with examples from the natural world, to show how neurons first allowed animals to develop simple forms of attention and then to construct awareness of the external world and of the self. His theory has fascinating implications for the future: it may point the way to engineers for building consciousness artificially, and even someday taking the natural consciousness of a person and uploading it into a machine for a digital afterlife.