written by William Joyce, illustrated by William Joyce and Joe Bluhm (I'm going to meet them sometime in March)
I first encountered this story when the animated short based on the book was nominated for (and later won) an academy award. The short is very good, and I recommend you watch it. In fact, I would recommend watching it over reading the book (though I'm interested to download the app now).
The story is good, but it lacks the punch the film had for me, which surprised me, since the text emphasizes the importance of words and the film has no dialogue. Something about the book is just less exciting than the film. It's still a solid picture book worth checking out.