Yesterday evening I spoke at Treadwell’s Bookshop in London on ‘Magical Stones and Gems in Pre-Modern England’, drawing largely on the Peterborough Lapidary (my translation of which was published in October 2016). The text of my paper can be downloaded here. The Peterborough Lapidary, dating from the fifteenth century, is the longest and most comprehensive medieval English treatise on the magical properties (‘virtues’) of stones. My talk focussed on the magical properties ascribed to stones in the Lapidary, including powers of divination and the ability to summon spirits, repel witches and even raise the dead. It is always a pleasure to speak at Treadwell’s and I am grateful to Christina and all the staff and volunteers at what is probably the most interesting bookshop in the country for making this event possible. I was especially delighted to see two of my former students in the audience, and had some fascinating conversations with a variety of people after the talk.