The Imaginarium Geographica is an atlas of the Archipelago of Dreams, an island chain that is the basis for many "fictional" lands. It is the primary responsibility of the Caretakers, who edit, revise, and add on to the maps as necessary. The badger Tummler created a pocket version in the common language, mass-printed it, added a forward by the King Artus, and sold it in his bookstore (alongside his cookbook). The book was a massive success, and was distributed throughout the archipelago. The original version contains various spells and hidden messages, and is one of the most sought-after treasures in the Archipelago (alongside the Dragonships).