A core philosophical project is the attempt to uncover the fundamental nature of reality, the limited set of facts upon which all other facts depend. Perhaps the most popular theory of fundamental reality in contemporary analytic philosophy is physicalism: the view that the world is fundamentally physical in nature. The first half of this book argues that physicalist views cannot account for the evident reality of conscious experience and hence that physicalism cannot be true. However, the book also tries to show that familiar arguments to this conclusion—Frank Jackson’s form of the knowledge argument and David Chalmers’ two-dimensional conceivability argument—are not wholly adequate. The second half of the book explores and defends a radical alternative to physicalism known as “Russellian monism.” Russellian monists believe that (i) physics tells us nothing about the concrete, categorical nature of material entities, and that (ii) it is this “hidden” nature of matter that explains human and animal consciousness. Throughout the second half of the book various forms of Russellian monism are surveyed, and the key challenges facing it are discussed. Ultimately the book defends a cosmopsychist form of Russellian monism, according to which all facts are grounded in facts about the conscious universe.