In the interval between the epics of Homer…and the age of the three great tragic poets, thinkers began to explore the various phenomena of the external world and came to understand many aspects of nature which had hitherto been shrouded in complete mystery. The creative literary activity of this epoch likewise betokens on the part of the Greeks an increasingly higher level of self-understanding and self-consciousness, in the best sense of the word. At this time appeared a group of lyric poets, who had looked deeply within their own natures, and through the vehicle of their poetry, made abundantly evident how thoroughly they understood the essential character of man’s inner being. In Greek tragedy as we now have it we meet a fully developed dramatic form….The influence of tragedy on classic comedy is evident in the increasing preoccupation with subjects that are utopian or timeless, [while] the traditional satire on contemporary events and personages recedes more and more into the background.

– from the Introduction, by Whitney J. Oates and Eugene O'Neill, Jr.