In _Form, Matter, Substance_, Kathrin Koslicki defends a hylomorphic analysis of concrete particular objects (e.g., living organisms). The Aristotelian doctrine of hylomorphism holds that those entities that fall under it are compounds of matter (hulē) and form (morphē or eidos). Koslicki argues that a hylomorphic analysis of concrete particular objects is well-equipped to compete with alternative approaches when measured against a wide range of criteria of success. A successful application of the doctrine of hylomorphism to the special case of concrete particular objects, however, hinges on how hylomorphists conceive of the matter composing a concrete particular object, its form, and the hylomorphic relations which hold between a matter-form compound, its matter and its form. Through the detailed answers to these questions Koslicki develops in this book, matter-form compounds, despite their metaphysical complexity, emerge as occupying the privileged ontological status traditionally associated with substances, due in particular to their high degree of unity.