The book opens, essentially, with Thomas discovering an abandoned stray on her mother's porch and taking him in when she goes back home. At home, the new dog, Sundog, is entirely disregarded by Thomas' aging dogs, who are the last three from her prior "experiment". Thomas is perplexed by Sundog's human-centric behavior, his apparent Obedience and training, and the decisions that he makes in this regard. He's a good dog, and a confident dog, and wants to be around Thomas and her husband. She seems happy about this obedience, but never really teaches Sundog anything else, and other than trips to the vet and things like that, none of the dogs are ever on leashes.
The old dogs pass, in time, and other dogs get added to the mix. Misty is a Belgian Sheepdog from an AKC breeder, and has spent her life in a crate, let out a couple of times a day in a fenced 3 foot concrete area to relieve herself with the other dogs. At the start, Misty sounds very much to me like Simple Dog (behaviorally speaking, not in appearance), as described in Hyperbole and a Half, but after some time in Thomas' entirely without-boundaries household, she relaxes and is able to gain some autonomy and realize that she can make some decisions about herself. Well, almost without boundaries household; chasing cars is not permitted, and apparently Thomas keeps an electric collar on hand for situations such as those, to train dogs off of that.
Other dogs get added to the mix, still without leashes and boundaries, and it more or less shuffles itself out. There are a number of cats as well (a large and consistently growing number, in fact), and the animals form themselves into a couple of different social groups, most with at least one human involved. There is a certain amount of kindness in Thomas' approach, as the animals are fed twice a day, don't seem to receive physical corrections (unless the shock collar comes out), and have a great deal of affection from the humans.
With each dog, Thomas does what she calls an intelligence test, or rather what she says people claim is an intelligence test. She puts a dog biscuit under a towel and judges each dog's reaction. This book was published in 2000; there is more to testing canine intelligence than that, even in the home, and I'm not sure why Thomas doesn't seem aware of that, with the reading and correspondence and conferences and things that she does. Some of it is, as Thomas says, an adaptation of Piaget studying object permanency in human children, but there is more, and this test is more involved, and developed by Dr. Stanley Coren, who I tend to think kind of knows what's going on with regards to dog behavior and intelligence. This isn't to say I think Thomas is incorrect; only incomplete.
Overall, it was an interesting read, and certainly less unsettling than The Hidden Life of Dogs; Thomas still puts a lot of stock in pack and pack hierarchy, though in the context of family-style groups. She observed wolves in several different contexts, and isn't stuck on the same page as Cesar Millan, anyway.