The Lesser Key of Solomon (Lemegeton) is not one work but a compilation of five separate texts brought together under a Solomonic title, most likely in the seventeenth century, from older materials. The five are the Ars Goetia (the catalogue of demons), the Theurgia-Goetia (spirits of the compass points, both good and evil), the Ars Paulina (angels of the hours and of the degrees of the zodiac), the Ars Almadel (angels of four "altitudes," worked with a wax tablet), and the Ars Notoria (prayers for attaining knowledge and memory, and the oldest of the five). The unifying attribution to Solomon is legendary, and the parts differ markedly in tone and origin, the Ars Notoria is a genuinely medieval text of pious prayer for learning, while the Ars Goetia is a catalogue of spirit-binding.
The Ars Goetia's list of seventy-two spirits draws directly, and in most scholars' view derivatively, on Johann Weyer's Pseudomonarchia Daemonum of 1577, part of a printed treatise arguing that belief in witches was often demonic delusion, which makes the taxonomy's origin ironic: a catalogue meant to help clergy identify demonic deception was later stripped of that critical framing and repurposed as a practical operator's manual. The Ars Notoria, generally judged the oldest of the five component texts, has a documented medieval manuscript history distinct from the others, consisting of prayers and diagrams meant to grant swift mastery of the liberal arts, a devotional aim closer to angelic petition than to the demon-binding it now shares a cover with. Crowley's 1904 edition, from a manuscript transcribed by Mathers, fixed the modern standard text and title.