Two weeks before his death, Oliver Sacks outlined the contents of The River of Consciousness, the last book he would oversee. The best-selling author of On the Move, Musicophilia, and The Man Who Mistook His Wife for a Hat, Sacks is known for his illuminating case histories about people living with neurological conditions at the far borderlands of human experience. But his grasp of science was not restricted to neuroscience or medicine; he was fascinated by the issues, ideas, and questions of...