W. Bruce Cameron has successfully voiced how dogs think and feel, especially dealing with our loyalty to our owners. Yes, humans are weird and do adorable things, but we still love them and would do anything for them.
I don't want to give away too much of the story, so I won't go in to too much detail, but it's basically a dog trying to find what his true purpose is, through his many lives (reincarnated) from puppy to adult dog.
What he discovers is a great message for dogs and humans alike, and makes for a beautiful, heartwarming story.
For more info and to buy the book, check out its Amazon page.