An updated & slightly abridged English translation of the author's previous work on the 5th century B.C. Neoplatonist Hierocles, published in various places. This work allows Hierocles' median position in the history of Neoplatonic philosophy, between Iamblichus & Syrianus-Proclus, to emerge. Contents: (I) Biographical Elements; (II) Hierocles' Ideas on the History of Platonic Philosophy; (III) Hierocles' Philosophical Ideas on Matter, the Demiurge, & the Soul; & (IV) Hierocles' Philosophical Ideas on Providence. Translated from the French.