On Sleeping and Waking (Greek: ΠΕΡΙ ΥΠΝΟΥ ΚΑΙ ΕΓΡΗΓΟΡΣΕΩΣ; Latin: DE SOMNO ET VIGILIA) is also known as On Sleep and Sleeplessness. In this book Aristotle discusses the relationship between sleep and the body, soul and sensation. Translated by William Alexander Hammond. Painting: Le Sommeil by Gustave Courbet, 1866. LibriVox recording and cover design by Geoffrey Edwards are in the public domain.