What can Mary know about the conscious experience of color from inside her black and white room, and what follows for the metaphysics of consciousness? Torin Alter gives a state-of-the-art analysis of these issues. He focuses especially on the crucial gap between structural and phenomenal aspects of reality, and articulates a powerful version of Russellian monism that traces this gap to a deep level of the physical world. Along the way he gives a definitive defense of anti-materialist arguments from objections old and new, shedding new light on this crucial nexus between consciousness, knowledge, and reality.