This grimoire, or handbook of magic, was confiscated by the Venetian Inquisition in 1636 from practicing witches. After decades of searching for this elusive text, I now have the pleasure of presenting and translating it here for the first time. It contains their secret techniques for dealing with the more dangerous spirits or daemons, intentionally scattered and hidden within a collection of "secrets" comprising many detailed examples. Together these provide enough clues to enable practitioners to create their own spells for working with all the spirits cataloged. It distinguishes itself as a supplement to the better known Clavicula Salomonis ("Key of Solomon"); whereas that text focuses on aerial spirits, this one focuses on chthonic spirits. This text is one of the primary original sources for the popular Grimorium Verum.