IN some ways it is regrettable that consideration of the Timaeus has been dominated in recent years by the controversy concerning its place in the sequence of Plato’s dialogues. Plato’s recognition of a duty to say what he could about the physical universe and to enter seriously into Greek enquiry περì φύσεως makes this dialogue, or rather Timaeus’ monologue, of outstanding significance—wherever the dialogue belongs in relation to the rest. Anyone approaching the subject should read first G. E. R. Lloyd’s article on ‘Plato as a Natural Scientist’ in JHS 88 (1968), 78–92. We have recently a contribution from Vlastos in Plato’s Universe (Oxford, 1975), a series of lectures given at the University of Washington, with annotations on various cruces of the dialogue.