This fascinating book explores the history, techniques, and cultural significance of medieval aquamanilia, cast metal objects used to pour water for hand washing in religious and secular contexts. Usually created in appealing animal or human forms, aquamanilia feature two openings, one for filling and the other for pouring. They represent the first emergence of hollow-cast vessels in Western Europe and a significant development in the history of technology. The book presents and catalogues the entire aquamanilia collection of The Metropolitan Museum of Art for the first time, as well as selected examples from other collections and other related medieval objects.