Casting Bones - same as that used by witch doctors.
This powerful magic item was created to augment Alienists, a prestige class in the Tome and Blood.
Circlet of Amplus Ater Iris meaning “Circlet of The Great Dark Messenger” (Amplus - great, important; Ater - dark, malicious; Iris - messenger of the gods. Thought by some to mean Nyarlathotep)
It looks like a cook's book. It is a cook's book. It is also where the cook, who happened to be a master spy, encoded all his secrets and contacts. The book has innocently fallen into your group's hands. Everyone wants it, and many are not subtle or peaceful in their attempts.