The Malleus Maleficarum (Latin for "The Hammer of Witches", or "Hexenhammer" in German) is one of the most famous medieval treatises on witches. It was written in 1486 by Heinrich Kramer and Jacob Sprenger, and was first published in Germany in 1487. Its main purpose was to challenge all arguments against the existence of witchcraft and to instruct magistrates on how to identify, interrogate and convict witches.

The Malleus Maleficarum was written by Heinrich Kramer and Jacob Sprenger in 1486. Both men were members of the Dominican Order and Inquisitors for the Catholic Church. They submitted the Malleus Maleficarum to the University of Cologne's Faculty of Theology on May 9, 1487, seeking its endorsement. Instead the faculty condemned the work as unethical and illegal. However, Kramer still inserted an endorsement from the University into subsequent editions.

The Catholic Church banned the book in 1490, placing it on the Index Librorum Prohibitorum. Despite this, the Malleus Maleficarum became the de-facto handbook for witch-hunters and Inquisitors throughout Late Medieval Europe. Between the years 1487 and 1520, it was published thirteen times, and between 1574 to 1669 it was again published sixteen times. The papal bull and endorsements which appear at the beginning of the book contributed to its popularity by giving the illusion that it had been granted approval by Pope Innocent VIII.

The Malleus Maleficarum perhaps owes most of its popularity to Johannes Gutenberg. It was the invention of the printing press in the middle of the fifteenth century that allowed the work to spread so rapidly throughout Europe.