Thornton Rabbit worries about everything until he meets an old man who worries about nothing.
Thornton doesn't have time for any friends or activities because he is busy worrying. He worries about every remotely possible disaster--until he meets a man who doesn't worry at all though his house is perched precariously on the edge of a mountain. The house falls off the mountain, the man still doesn't worry about finding another, and Thornton takes the cue: "Perhaps I do not have to worry about everything."
The full page pencil sketches are charming and the faces of the characters are remarkably expressive. I particularly like the way the illustrations show the changes in Thornton's attitude and behavior through facial expressions and body language.