Of all the texts, of all the spells, this is the most cursed.
— Joan Clayton
The Poetry of Death is an old tome of occult knowledge known to contain dark secrets, and written in the Verbis Diablo, the language of the Devil. It was kept in secret for many years by Joan Clayton, who never dared to open it herself, and who advised Vanessa Ives to do the same. She told Vanessa that it should only be opened if she was crushed and beaten, and her God deserted her completely. Vanessa chose to leave the book where it was in the Cut-Wife's cottage when she left, replacing the Cut-Wife's ward protecting the site from evil, but doing little else to ensure the protection of the book.
In her hubris Vanessa dismissed the Cut-Wife's warning years later and opened the book after having an unpleasant encounter with Clayton's murderer Sir Geoffrey Hawkes. Therein she found an incantation that drove Sir Geoffrey's dogs mad and set them upon him even though she was in the cottage a long distance from Sir Geoffrey's estate.