This book is an excellent read, it is the ONLY book i have read (of which there are lots) to split the different barks into catagories, (including a written idea of what each bark sounds like) so that you can truly discover why your dog is barking, making the training to prevent unwanted barking much easier. My dog isn't completely cured but as the book says some dogs need to vocalise how wouold we like being told never to speak again? This book helped me not only understand my dog, but also to understand others whilst out. I can now recognise the differences between barks, and am more aware if the dog is a threat to us or not. A MUST for ALL dog owners, as so many dogs are branded as potentially aggressive due to a vocal nature, (mine included until i got this book) when the reality of the fact is most barking is done by scared, insecure, excitable dogs, and most aggressive dogs don't actually bark before an attack!
The only problem is if like mine your dog has a mixture of barking triggers,(due to a shaky puppyhood) is doesn't really cover what to do when your dog is an exciteable barker, protective barker, and fear barker all within the same trigger. Which bark to train out first and which is the priority. But most dogs aren't like mine and usually have only 1 trigger and 1 issue to cause problem barking.