These hours of backward clearness come to all men and women, once at least, when they read the past in the light of the present, with the reasons of things, like unobserved finger-posts, protruding where they never saw them before. The journey behind them is mapped out, and figured with its false steps, its wrong observations, all its infatuated, deluded geography.Henry James,The Bostonians, ch. xxxixThis paper is intended to contribute to the study of both Homer and Greek tragedy, and more particularly to the study of the influence of the epic upon the later poets. The current revival of interest among English scholars in the poetic qualities of the Homeric poems must be welcomed by all who care for the continuing survival and propagation of classical literature. The renewed emphasis on the validity of literary criticism as applied to presumably oral texts may encourage a more positive appreciation of the subtlety of Homeric narrative techniques, and of the coherent plan which unifies each poem. The aim of this paper is to focus attention on a number of elements in Greek tragedy which are already present in Homer, and especially on the way in which these poets exploit the theme of knowledge—knowledge of one's future, knowledge of one's circumstances, knowledge of oneself. Recent scholarship on tragedy has paid much more attention to literary criticism in general and to poetic irony in particular: these insights can also illuminate the epic. Conversely, the renewed interest in Homer's structural and thematic complexity should also enrich the study of the tragedians, his true heirs.