This book examines the metaphysical issues regarding the powerful qualities view in all its various forms. The author also develops and defends his own version of the powerful qualities view, which he calls powerful categoricalism. In recent years, the powerful qualities view about the nature of properties has received considerable attention in the philosophical literature. The core tenet of the powerful qualities view is that properties are both dispositional and categorical/qualitative. Despite the increased popularity of the powerful qualities view, there is no book-length presentation of the view in its distinct versions. The first part of this book analyzes the advantages and drawbacks of each version of the theory paying special attention to those difficulties that make it unstable and perhaps incomprehensible. In the second part, the author shows how a developed version of a dualist model for the origin of natural modality—according to which the specific behaviour of things in the world is the outcome of both the thin power properties have to be nomically relatable and certain nomic relations that determine properties’ nomological role—can support an alternative understanding of the main tenet of the powerful qualities view. This part, in combination with the discussion of the difficulties of the other versions, not only defends the tenability of powerful categoricalism but also its superiority over the other extant versions. The Metaphysics of Powerful Qualities makes an original contribution to an ongoing debate in contemporary metaphysics.