In this paper I want to suggest that, while the argued philosophical distinction between logic, epistemolgoy and ontology is one of the many achievements of Aristotle, his predecessor Parmenides was in fact already operating with a theory of knowledge and an elementary propositional logic that are of abiding philosophical interest. As part of the thesis I shall be obliged to reject a number of interpretations of particular passages in his poem, including one or two currently fashionable ones. Since so much (...) turns on points of translation, I note for purposes of comparison what seem to be significant alternatives to my own in any particular instance. The line numbers are those of the DK text. (shrink)