Barkley by Rebecca Crane

This is the story of a small dog named Barkley who is having a bit of an identity crisis.

Barkley sees all the dogs around him, and they each have something that makes them unique—big dogs, fluffy dogs, long dogs, fierce dogs. But what kind of dog is Barkley? Just imagine his surprise when he discovers he's a LOST dog. Luckily, his owner Max helps him realize he's more than just that: he's a best friend dog, and that makes him a happy dog, too. And you can't ask for much more than that.