Since his late teens, Louis Proud has suffered from chronic sleep paralysis and has undergone hundreds of such episodes, many of them terrifying but ultimately transformational and eye-opening. These experiences, he believes, allow access to the "spirit realm" and could well hold the key to a whole host of paranormal phenomena, including poltergeist disturbances, out-of-body-experiences, mediumship, spirit possession, and succubi and incubi encounters. Drawing on the work of Colin Wilson, Joe Fisher, Stan Gooch, Whitley Strieber, Robert Monroe, Dion Fortune, and a number of other paranormal experts, Proud lucidly demonstrates that many sleep paralysis experiences involve genuine contact and communication with incorporeal entities, some of them parasitic and potentially dangerous. In this comprehensive, open-minded exploration of the sleep paralysis phenomenon, filled with fascinating descriptions of his own experiences, as well as those of others, no stone is left unturned as Proud attempts to get to the bottom of the mystery.