For half a millennium the printed book has been the primary means of communicating ideas in the Western world. The history of Roman literature effectively begins with Ennius. Plautus in his comedies had reproduced his Greek models in metres in which the influence of native Latin verse is apparent. Roman educational institutions, predictably, follow Greek models. The casual and fluid nature of publication in the ancient world is described just as characteristic of what happened to books after publication. For educational and rhetorical purposes epitomes and abstracts were increasingly in vogue. Roman scholars took over the traditions of Alexandrian literary scholarship along with the rest of Hellenistic culture. From Virgil onwards Latin poetry was profoundly influenced by rhetoric, and a style of literary criticism that fails to take account of this fact will miss much that is essential to the poetry. Literary Latin was an artificial dialect, quite distinct from the spoken idiom.