Pseudomonarchia Daemonum
Liber Officiorum Spirituum (English: The Book of the Office of Spirits) was a demonological grimoire and a major source for Johann Weyer's "Pseudomonarchia Daemonum" and the "Ars Goetia". The original work (if it is a single work) has not been located, but some derived texts bearing the title have been found, some in the Sloane manuscripts, some in the Folger Shakespeare Library. Each version bears many similarities to each other and to the "Pseudomonarchia Daemonum" and the "Ars Goetia", though they are far from identical.