A Medieval Book of Magical Stones is the first translation of the longest and most comprehensive medieval English treatise on the occult powers of stones and gems, the Peterborough Lapidary. Lapidaries (encyclopaedias of the 'virtues' of stones and minerals) were an essential resource for practitioners of natural and ritual magic as well as medicine. This late fifteenth-century manuscript from the library of Peterborough Cathedral describes 145 stones, portraying them as living beings whose properties range from giving the bearer the power to command spirits and foretell the future to healing...