The Malleus Maleficarum is one of the best-known treatises dealing with the problem of what to do with witches. Written in 1487 by a Dominican inquisitor, Heinrich Institoris, following his failure to prosecute a number of women for witchcraft, it is in many ways a highly personal document, full of frustration at official complacency in the face of a spiritual threat, as well as being a practical guide for law-officers who have to deal with a cunning, dangerous enemy. Combining theological discussion, illustrative anecdotes and useful advice for those involved in suppressing witchcraft, the treatise's influence on witchcraft studies has been extensive. The only previous translation into English, that by Montague Summers in 1928, is full of inaccuracies. It is written in a style almost unreadable nowadays, and is unfortunately coloured by Institoris's personal agenda. This new edited translation, with an introductory essay setting witchcraft, Institoris and the Malleus into clear English, corrects Summers' mistakes and offers an unvarnished version of what Institoris actually wrote. It will undoubtedly become the standard translation of this controversial late medieval text.