Walkin' the dog / by Chris Lynch.

Enhanced descriptions from Syndetics:

"Lynch is back and better, smarter, and funnier than ever." --Jacqueline Woodson, National Book Award Winner

A boy learns how to be a friend from man's best friend in this funny and moving middle grade novel about humans being able to change and dogs changing us from acclaimed author Chris Lynch.

In a family of strong personalities with very strong points of view, Louis is what his mother lovingly calls "the inactivist," someone who'd rather kick back than stand out. He only hopes he can stay under the radar when he starts high school in the fall, his first experience with public school after years of homeschooling.

But when a favor for a neighbor and his stinky canine companion unexpectedly turns into a bustling dog-walking business, Louis finds himself meeting an unprecedented number of new friends--both human and canine. Agatha, a quippy and cagey girl his age always seems to be telling two truths and a lie. Cyrus, a few years his senior, promises he's going to show Louis how to be a better person, whether Louis wants him to or not. And then there are the dogs: misbehaving border terriers, the four (possible stolen) sausage dogs, the rest of Louis's charges, and a mysterious white beast who appears at a certain spot at the edge of the woods.

Dogs and human alike all seem to have something they want to teach Louis, including his menacing older brother who keeps turning up everywhere. But is Louis ready to learn the lesson he needs most: how to stop being a lone wolf and be part of a pack?