First, it's important to understand the difference between true "separation anxiety" (a disorder that may require the use of anti-anxiety medicine) and behavioral problems that can mimic separation anxiety.
For example, urination or defecation in the house while left alone may be due to improper housetraining or to a medical cause, rather than being a symptom of "separation anxiety." Likewise, destructive behavior while left alone may simply due to boredom or (with puppies) teething.
Dr. McConnell fully explains what separation anxiety is – as well as what it isn't. She gives tips for dealing with problems that are "just" bad habits, so this is a good booklet even if your dog turns out not to have true separation anxiety.
Just as importantly, Dr McConnell explains how to prevent separation anxiety in dogs who haven't developed it yet. This includes "quiet but loving comings and goings," teaching your dog how to be comfortable in a crate, and making sure your dog is getting sufficient exercise.
If your dog does have separation anxiety, the "Treating Separation Anxiety" section spells out the things you need to do – and not do! – to help your dog overcome her anxiety. There's no "quick fix" - a typical behavior modification program will take several weeks (at a minimum) before you'll get to the point where you can consider the dog "cured."
But you and your dog will both heave sighs of relief once the agonizing symptoms of true separation anxiety are conquered.