One of the most notorious books within the field of Demonology is 'The Lesser Key Of Solomon, also widely known as the 'Goetia' this book contains detailed descriptions of spirits and demons and the conjurations required to invoke them.  Said to have been written by 'King Solomon' the Goetia details protective rites necessary to prevent the spirits from gaining control.  The Lesser Key of Solomon also provides detailed instructions on how to create certain necessary instruments required by these rituals.

The Lesser Key of Solomon provides instructions for the summoning of the 72 different demons called upon by King Solomon.  These demons include: Bael (a king of hell), Agares (a duke of hell - gains pleasure from teaching immoral expressions) and Vassago (a prince of hell with the power of telling past and future).

The final pages of the Lesser Key of Solomon tell of how king Solomon learnt of these demonic arts and rituals after being visited by an angel.