From publisher blurb:
The Grand Grimoire is a supplement for Medieval Tales that introduces the "Practitioner's Art" to the game. This book includes:
A discussion of the origins of magic in the West, how it works, and who can use it;
Six categories of magic: Alchemy, Enchantment, Divination, Invocation, Maleficia, and Theurgy;
Rules on the use of esoteric reagents and enhancing components;
A discussion of real-life grimoires - historical sources on magical knowledge - that existed in the 15th century, and how characters can acquire (and master) them;
Well-known magical operations such as the creating of homunculi and golems, familiars and mandrakes, summoning demons, contacting spirits, creation of the Hand of Glory, and more - along with rules for how these operations can be performed by player characters.
The Grand Grimore contains no fewer that 300+ spells and operations, all accurately recreated using historic descriptions in medieval texts. Many are drawn from folklore, or the records of contemporary witch trials such as those of Alice Kyteler and Giles de Rais.