Felix Hemmerlin, also known as Maleolus in Latin (a translation of his German surname, which means “little hammer”), was born to a rich family that was part of the old Zurich bourgeoisie. As such, he was allowed access to religious education: he studied in Erfurt and Bologna and became a clerical canon by his twenty-third birthday. While he is most famously remembered for his writings on witchcraft, Hemmerlin was an important intellectual figure of his generation and wrote on an array of issues. He was also involved in politics and was considered by some to be one of the most brilliant minds in German-speaking Switzerland at the time. He was frequently critical of the Church and spoke out against them on many occasions: this has inspired historians to refer to him as a forerunner of the Reformation. For example, despite his negative view of the peasantry, Hemmerlin defended the lower classes against the abuse of clergy members. Furthermore, he blamed the laypeople's frustrations in Bohemia on the taxes levied by the Church. However, this direct, outspoken approach made him many powerful enemies.

Hemmerlin was a big proponent of his native city of Zurich, and when a civil war arose between Zurich and the other Swiss states, he supported Zurich's claims and their alliance with Hapsburg Austria. When the conflict was resolved and Zurich reunited with the other Swiss states, Hemmerlin became the primary enemy of the Swiss confederates; he was promptly seized, lost his clerical titles, and was imprisoned for the remainder of his life. 

In the above image from the Opuscula et tractatus, Hemmerlin is portrayed in clerical attire of the time. He has a small hammer in his left hand, a reference to his name. His head is surrounded by flying insects, which is a possible nod to his work on spells involving insects: Hemmerlin was the first to describe and bring forth the formula for exorcising and summoning pestilent insects. He mentioned how he had found the spell by accident in a 1452 publication, and inquisitors used his writings on the subject during the witch trials of later decades.