This volume investigates the foundational metaphysical questions regarding the unity and identity of substances within the Aristotelian framework. Edited by M.L. Gill, David Charles, and T. Scaltsas, the collection brings together fourteen essays from prominent scholars in ancient philosophy and contemporary metaphysics. The authors analyze the ontological status of essences, their distinction from other substance components, and the logical relationships governing these entities.

Experts recognize this volume as a significant contribution to the study of Aristotle's Metaphysics, particularly for its bridge between historical exegesis and modern metaphysical debate. Readers frequently note the academic density of the prose, making it a resource primarily intended for advanced students and professional philosophers.