Who are the familiar spirits of classical culture and what is their relationship to Christian demons? In its interpretation of Latin and Greek culture, Christianity contends that Satan is behind all classical deities, semi-gods, and spiritual creatures, including the gods of the household, the lares, and penates. But this book argues that the great thinkers of the Italian Renaissance had a more nuanced and perhaps less sinister interpretation of these creatures or spiritual bodies. The form of the body relies on the spirits' knowledge of their human interlocutors' pasts. But their core trait is compassion, and sometimes their odd, eerie arrivals are seen as harbingers or warnings to protect the people. It comes as no surprise then that when spiritual beings distort the natural world to communicate, it is vital that one begins to listen.