Born in New Mouse City, capital of Mouse Island, Geronimo is Rattus Emeritus of Mousomorphic Literature and of Neo-Ratonic Comparative Philosophy.

He runs The Rodent's Gazette, the most famous newspaper of the island, founded by his grandfather William Shortpaws. In his spare time, Geronimo collects antique cheese rinds from the 18th century, but writing books is the thing he loves the most, and he is an exceptionally successful author: his books have been translated into 52 languages and they have sold more than 187 million copies worldwide!