Substance and the Fundamentality of the Familiar explicates and defends a novel neo-Aristotelian account of the structure of material objects. While there have been numerous treatments of properties, laws, causation, and modality in the neo-Aristotelian metaphysics literature, this book is one of the first full-length treatments of wholes and their parts. Another aim of the book is to further develop the newly revived area concerning the question of fundamental mereology, the question of whether wholes are metaphysically prior to their parts or vice versa. Inman develops a fundamental mereology with a grounding-based conception of the structure and unity of substances at its core, what he calls substantial priority, one that distinctively allows for the fundamentality of ordinary, medium-sized composite objects. He offers both empirical and philosophical considerations against the view that the parts of every composite object are metaphysically prior, in particular the view that ascribes ontological pride of place to the smallest microphysical parts of composite objects, which currently dominates debates in metaphysics, philosophy of science, and philosophy of mind. Ultimately, he demonstrates that substantial priority is well-motivated in virtue of its offering a unified solution to a host of metaphysical problems involving material objects.