George Grote undertakes a searching examination of Plato's Timaeus, centered on one of its most disputed passages: did Plato mean the Earth to move, or to remain fixed at the center of the cosmos? The question turns on a difficult Greek term and has divided ancient authorities such as Aristotle, Cicero, Plutarch, Proclus, and Simplicius, as well as modern scholars including Cousin, Martin, Gruppe, and Boeckh. Grote rejects both the claim that Plato anticipated Copernican heliocentrism and the opposite claim that he must have taught an unmoving Earth. Instead, he argues that Plato may have combined the daily rotation of the heavens with the Earth's own motion without seeing any contradiction. Grote develops a nuanced reading of the Earth as bound to the cosmic axis, not merely passively resisting the heavens but helping sustain their order and the cycle of day and night. He uses linguistic analysis, comparisons of physical fastening, and Aristotle's testimony in De Caelo to show that rotation is implied by context rather than by the word itself. Along the way, he challenges Boeckh's, Martin's, and Cousin's interpretations, treating the passage as a revealing case study in Platonic cosmology and the hazards of reading later astronomy back into ancient philosophy. This edition has been fully restored with modern typesetting, custom cover design.