The Book of Shadows (or "BoS") is sort of a customized reference book for Wiccans, containing useful information such as myths, liturgical items, one's own writings or records of dreams and magical workings. According to Gerald Gardner, such a book should be handcopied from teacher to student but in practice not every Wiccan has a "book of shadows" and few are exactly alike. Sometimes only initiates are allowed access to a tradition's book, or it may be called by a different name, such as "mirror book," "magical diary" or "grimoire."