The Malleus Maleficarum, or "Hammer of Witches," was a popular medieval handbook for witch hunters, prosecutors, and executioners—and the source of a popular Newberry ghost story.
In 1985 the Chicago Tribune reported that, while part of an exhibition on the Inquisition at the Newberry, the "Hammer of Witches" turned slightly in its cradle everyday. According to the Tribune, the Malleus Maleficarum, in a locked case and untouched by anyone, magically moved 30 degrees over a weekend.
Separated into three parts, the Malleus Maleficarum tells us about the complete process of witch-hunting. Part one discusses "the devil, a witch and the permission of almighty God" as the concomitants of witchcraft. Part two focuses on the methods of witchcraft and how to annul or dissolve them. The last part concludes with information about the judicial proceedings in the church and civil courts. Not only the content, but also the format, explains its popularity. Each part is divided into sections that answer a question, very much like "frequently asked questions" sections on websites. It was easy to use and enabled readers to quickly look up information.
Three years prior to Malleus Maleficarum's publication, its authors, Heinrich Kramer (Latinized as Institoris) and Jacob Sprenger, received a Papal bull from Pope Innocent VIII supporting their witch-hunting activities. As a book by authors with Papal approval, it may have had more credibility than other handbooks.
As for the eerie behavior of the book in 1985, perhaps it was witchcraft—or perhaps it was the rumble of buses on Walton Street.
No one is certain—but one thing is: the Newberry has not exhibited the book since.