Another very good book on positive training. This one has an introductory chapter on the history of dog training methods, and then a very clear discussion of Dahl's own philosophy of training, along with her credentials and background.
The book focuses on problem behaviors -- nuisance barking, separation anxiety, poor leash manners, humping visitors, etc. -- and how to change them. It's designed as a reference tool, rather than as something to be read from cover to cover, so there's lots of repetition. And the writing itself is pretty clunky. The advice and training tips seem great, although a few pictures would help me understand some of her suggestions better.