This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book aims to show the centrality of a proper ontology of properties in thinking about consciousness. There is a need for a clear account of an ontological status of properties that can serve as a framework within which questions regarding the hard problem of consciousness can be properly pursued. One way forward is to reflect systematically on what the issues are, hence engaging with the ontology of consciousness. One key reason for this has to do with the fact that consciousness raises multifaceted issues and questions which resist being boxed into one particular domain of inquiry. John Heil's 'The Mystery of the Mystery of Consciousness' sets the initial tone for subsequent discussions. As Heil sees it, the problem of consciousness may be rooted in these assumptions so much more than in the intrinsic nature of conscious experiences.