I just read this yesterday day and really loved it. I'm going to have to get it for my library. It's a brilliant wordless picture book with the cat escaping from an apartment and a little boy missing him. Both the cat and the boy wander around the city, the cat exploring and the little boy searching for his pet. Of course there's a happy ending. Plus in every spread, you must find Spot.
The art work is amazingly good. You could just start at the illustrations for hours!