What an extraordinarily frustrating experience.
1. The books main attraction is the author himself. Boy, does that guy love talking about himself. Easily 60% of the books content are solely about the author, nothing at all to do with dogs, let alone an answer to the question the title poses.
2. A whole lot of the remaining content is about other scientists studying dogs, wrong thesis, disproven conclusions, studies on other species and so on and so forth. Again, very little to do with actually correct facts about dogs, let alone why and how they love us.
3. And there is an enormous amount of repetition. It's common for the author to make the exact same points five or more times over 10-15 pages, without even changing the phrasing. Also, a lot of fluff, so for a book about a specific question, there is surprisingly little talk about that exact topic.
4. For someone who sets himself out to study the finer details about dog behavior, this guy has surprisingly little knowledge about dogs. Everyone who cared for a dog for any amount of time knows more about what makes dogs tick, than the author of this book (and apparently his students, who - we are repeatedly informed - are now professors here and there).
5. What clearly demonstrates this persons misguided believe of himself as an authority on ghe topic of dog, is a passage rather early in the book. He's talking about the dog Chaser who knows her 1200 toys by name, and how this isn't a question of intellect but training. Then he directly goes on to talk about his own "unfortunately stupid" adult adopted dog, who - for many months! - was unable to walk on leash without entangling herself on various object. Due to her stupidity.
Well, duh, if you would have trained her, she would have figured it out within 10 minutes. Who's stupid now? It's not like walking tethered to someone else by a leash is natural and instinctual walking behavior for an animal.
If you've already got this book, just skip ahead to page 166 and read to 200. Done. You won't miss anything you don't already know, or even already know better.
But beware: If you do read this part, don't believe everything he writes. Unfortunately he doesn't understand the cloning process either. Cloning involves an egg from someone to insert the DNA to be cloned. Cloning is not a sterile process without "contamination" with foreign DNA. So OF COURSE clones aren't actually replications of the original animal! Plus possible DNA mutation during multiplication etc. and so on. I don't get it, for a psychologist by training he really has forgotten a lot about his basic education.
If you're thinking about buying this book, safe yourself time, money and a lot of frustration and rather get yourself a fancy cup of coffee or something.