From the moment their second son arrived, the Little family noticed something different about Stuart. He was as small as a mouse, with the nose, tail, whiskers, and nature of a mouse. In fact, he was a mouse! So the Littles quickly adjusted their New York City lifestyle to meet their new son's needs—and they loved Stuart just as much as they loved his big brother George.

Of course, Stuart's life has its challenges. Being as small as a mouse in New York City isn't easy. There are window blinds, garbage disposals, and Snowbell the family cat to beware of. But there are also great joys, like racing across the lake in Central Park. Then one day, Stuart's dear friend Margalo the bird flees the city in fear and it's up to the young mouse to find her. Will Stuart survive in the country? Will he find his friend?

Garth Williams's ink sketches add even more life and personality to this wonderful story about loving life and embracing adventure.