A grimoire is often termed as an ancient book of occult knowledge.it contains spells formulas, correspondences and rituals. it is often associated with high magic. the key of solomon is a well known grimoire. a book of shadows is a witches, wiccans or pagans book of spells, formulas, rituals, correspondences, reflection, dreams, tarot readings etc, in short it is a private journal of a witch and contains whatever is deemed relevant by the witch. it is often kept secret and in many traditions it is burnt upon the death of the witch. i however would not burn it and rather pass it on to my children.