A Book of Shadows (BOS) is a collection of writings that reflect the core concepts of magical lifestyles and magical or nature based religions.   Most physical BOS are hand-written copies of rituals, recipes, formulas, crafts, lore, lessons and guidelines copied by the book’s owner from the books of those they have learned from.

Many BOS act as a kind of diary for the owner or a group, a place where not only data is recorded, but were the results of spells or recipes might be recorded.