The On Poems by the Epicurean philosopher and poet Philodemus of Gadara (1st century BC) survived amid the library of the Villa of the Papyri at Herculaneum, which was buried by the eruption of Vesuvius in AD 79. The papyrus-rolls in this, the only library that survives from the ancient world, are with the aid of advanced technology at last able to be read, reconstructed, and translated. The On Poems, in five books, offers unique insights into ancient literary criticism from Aristotle to Horace. Book 1 was published in 2000. This volume contains the Greek text, translation, and scholarly commentary on Books 3 and 4, together with the fragments of Aristotle's lost dialogue On Poets, many of which come from Book 4. These shed light on Aristotle's views on such controversial questions as mimesis, catharsis, and the origins of tragedy and comedy.