Respect for dogs.
Anybody considering keeping a dog should
learn at least a little about how a dog's mind works; the more you learn, the better your dog will respond to you.
There are many books available but, in my view, this one is way out in front. Patricia McConnell has a true gift for communication and an eminently readable style; even as a 'stand alone' this book is a good read - I learned a bit about relation ships in general along the way. Highly recommended.
