The material in the book is targeted at couples who have been married long enough to where they are beginning to experience "growing pains." The aim of the book is for couples to begin practicing what Doherty terms, "intentional marriage" as opposed to just letting the relationship run on autopilot.
The funny things is that all of the couples in our group (with the exception of Andrea and I) have been married two years or less. So in the case of our particular demographic, the material is serving as a very potent batch of "preventative medicine."
The discussion has been great. If you're looking for a good book to study in your own couples group, I'd recommend it. You can read a synopsis here.