This book offers a survey of the teachings of, and relations between, four leading figures in third-century Platonism: Longinus, Plotinus, Porphyry and Iamblichus. It documents and explains the coalescence of Aristotelian and Platonic elements in the Platonic tradition before the 3rd century, considers the effect of the new political environment on these thinkers, and argues that the antagonistic interests of the two older men (Longinus and Plotinus) were combined in the work of the two younger figures (Porphyry and Iamblichus) without sacrifice of coherence, rationality or fidelity to Plato. The authorship of the treatise on the sublime, the question of mysticism in Plotinus and the relation of Neoplatonism to ancient Christianity are among the topics discussed.