This monograph is the first study to assess in its entirety the fourth-century CE Latin translation of and commentary on Plato's Timaeus by the otherwise unknown Calcidius.The first part examines the authorial voice of the commentator and the overall purpose of the work; the second part provides an overview of the key themes; and the third part reassesses the commentary's relation to Stoicism, Aristotle, potential sources, and the Christian tradition.

This chapter examines the role of matter as an independent principle in the universe, and shows how Calcidius' borrows elements from Aristotle, the Stoics, and the "Pythagorean" Numenius to posit a minimal dualism.

This chapter examines Calcidius' position vis-à-vis and use of Stoicism, focusing on the themes of Providence and fate, the human soul, and matter, and argues that the Stoic influence is much stronger than commonly assumed, despite an overt polemic.

This chapter examines the extent to which matter can be said to have being, the role of the Platonic Forms, and the methods for discovering the metaphysical principles of the universe.

This chapter looks at the manner in which Calcidius presents allusions to Christian views (in comparison with known Christian authors of the era), his use of the "Hebrews," and his minimal reliance on Origen.

This chapter examines Calcidius' use of Aristotle, focusing on the topics of fate, the human soul, and matter.

This chapter examines Calcidius’ doxographical method, his view of the composition of the human soul, and the latter’s relation to the World Soul

This chapter examines how Calcidius sees his role as commentator in relation to his own translation, and his posiiton vis-à-vis the Platonist tradition.

This chapter reassesses the role of the divine and matter in Calcidius' commentary in comparison with views attested for Christian authors of this era, in order to highlight the incompatibility between the two worldviews.

This chapter argues against a commonly held assumption that Porphyry is (one of) Calcidius' (main) source(s), by comparing the fragments of the former's commentary on the Timaeus to Calcidius' approach, and analyzing more closely views attributed to Porphyry on the human soul, the transmigration of human souls into animals, matter, and Form.

This chapter examines how Calcidius sees the role of time in the universe; he posits an eternally existing world which owes its order to an atemporal divine cause.

This chapter examines how the first part of the commentary is connected to its second part.

This chapter argues that Providence is one of the key themes of the commentary, and examines how Calcidius (1) harmonizes Providence and fate with human free will through a notion of hypothetical necessity; and (2) refutes determinist positions, among which the Stoic view.