This work is designed to make Aristotle's three essays on sleep and dreams (De Somno et Vigilia, De Insomniis and De Divinatione per Somnum) accessible in translation to modern readers, and to provide a commentary with a contemporary perspective. It considers Aristotle's theory of dreams in historical context, especially in relation to Plato. It also discusses neo-Freudian interpretations of Aristotle and contemporary experimental psychology of dreaming. Aristotle's account of dreaming as a function of the imagination is examined from a philosophical perspective. The edition presents the Greek text, with facing-page English translation, introduction, notes and commentary.