The Malleus Maleficarum is a seminal treatise regarding witchcraft and demons, presented here complete with an authoritative translation to modern English by Montague Summers.
At the time this book was published in 1487, the Christian church had considered witchcraft a dangerous affront to the faith for many centuries. Executions of suspected witches were intermittent, and various explanations of behaviors deemed suspect were thought to be caused by possession, either by the devil or demon such as an incubus or succubus.
Kramer wrote this book after he had tried and failed to have a woman executed for witchcraft. Unhappy at the verdict of the court, he authored the Malleus Maleficarum as a manual for other witch seekers to refer to. For centuries the text was used by Christians as a reference source on matters of demonology, although it was not used directly by the Inquisition who became notorious for their tortures and murders.