"The Kingdom of Fantasy" is a children's novel written by Italian author Geronimo Stilton. The book follows the adventures of Geronimo, a mouse journalist who is magically transported to a fantasy world called the Kingdom of Fantasy.

In the story, Geronimo receives a mysterious invitation to visit the Kingdom of Fantasy from a queen who is in danger. He sets off on a quest to save her, encountering various magical creatures along the way, including fairies, trolls, and dragons. Throughout his journey, Geronimo must overcome challenges and use his intelligence and bravery to complete his mission.

The book is filled with vivid descriptions of the Kingdom of Fantasy, including its landscapes, creatures, and culture. It also teaches valuable lessons about friendship, courage, and perseverance, making it an engaging and educational read for children.