Among the many Platonists of the second century A.D., Albinus is one of the most important. He belongs to the period commonly known as 'Middle Platonism' which stands between the teachings of the Old Academy and the Neoplatonists. The Platonic Doctrines is the only complete philosophical textbook surviving from the ancient world and is the only fully-preserved work of Platonism from the time of Plato until that of Plotinus (circa 205-270 A.D.). The work was clearly intended to be an introduction to Plato's writings and is presented here in a definitive English language translation for the first time. The Platonic Doctrines surveys the topics of dialectic, metaphysics, mathematics, theology, physics, and ethics. The work provides good insights into the philosophical thinking which immediately preceded Plotinus, and anticipates some of the mystical theology of later centuries.