Geronimo sends valentines to all his friends but seems destined to spend the day alone.

"The phantom of the subway: When my sister Thea told me a ghost was haunting New Mouse City's subway tunnels, I had to get the scoop! So I set off with Thea, Trap, and my assistant editor Pinky Pick. But we were all in for the fright of our wee mouse lives...because the ghost turned out to be a CAT! The temple of the ruby of fire: It was my most thrilling adventure yet! My old friend Professor von Volt had discovered the location of the famous Ruby...

When Stilton cheese begins disappearing during Geronimo Stilton's trip to England he investigates to find the cheese thief.

My sister, Thea, is the mystery-loving rodent, not me! But somehow I found myself going undercover to get to the bottom of a case. Slimy Swiss balls -- I hardly knew where to start! Geronimo Stilton, Secret Agent Mouse? Maybe I could get used to that. ...

Watch your whiskers, Stilton: A mysterious one-eyed rat is trying to steal The Rodent's Gazette from under my nose! My manager came up with a plan to stop him. He arranged for me to appear on a TV quiz show. But if I lose I have to give up my tail! Shipwreck on the Pirate Islands: My sister, Thea, comes up with a new way to torment me. She's combined my two least favorite things: travel and ghosts! She heard rumors of a haunted pirate treasure buried...

Geronimo Stilton participates in the Race Across America on his bicycle with his friend Bruce Hyena.

Enter the world of Geronimo Stilton, where another funny adventure is always right around the corner. Each book is a fast-paced adventure with lively art and a unique format kids 7-10 will love.Geronimo Stilton, adventuremouse? Not me! But surely a little skiing couldn't hurt a rodent, right? Wrong. Moldy mozzarella! When my ski trip landed me in the hospital, I was sure it was going to be the worst Christmas ever! But my family and friends had something...

The discovery of an old map by his sister Thea leads Geronimo and his family to search for buried treasure on a faraway island.

"I invited my friend Petunia Pretty Paws to visit the Bay of Whales with me. But our trip got off on the wrong paw, and my relaxing vacation turned into a real nightmare. That is, until Petunia and I came across a great white whale that needed our help" (publisher).

Geronimo and his friends discover a huge oyster with an enormous pearl inside. After a feature article in the Rodent's Gazette, can they protect it from being stolen?