A fast, good read. Could work as a reference matter too, as continuing idea fodder for customer service improvements.
The overarching premise of the book is that knowledge of your existing customers is the greatest asset at your disposal. What follows from this premise are a number of methods for collecting and using customer information to improve your customer service.
Specifically, DiJulius makes use of a customer database to manage knowledge about customers. Companies can establish processes that allow their personnel to access the database information for their customers and provide a personalized experience. For example, at a high-end restaurant, you could keep information on top customers' drink preferences and have their drinks waiting for them at their table when they're seated. There were a lot of examples, but this kind of personalization was a main focus of the book.
Second, the book pushes the obviously good idea of focusing more of your marketing efforts on your current customers to get them to generate referral business, return for your services more often, and spend more when they do. This can also be accomplished using the database. If you know your product life cycle, and you're paying attention to when your customers are buying, you can market to them around the time when they're due to be purchasing again. He runs through several examples to show how initiatives like sending gift certificates to your regular customers for services of yours that they haven't used yet costs less and returns better results than general advertising. It is also DiJulius's view that retaining customers is more important than generating new customers.
For example, if you send one of your regular customers a $50 gift certificate to try out a service of yours that he isn't currently buying, you lose no money unless he redeems the gift certificate. If he does redeem the gift certificate for the service, he's already been qualified as one of your customers and is more likely to return for more of the same service than a random person who noticed a newspaper ad and is giving the service a first try.
There are a lot of specifics and little points in this book, but these two are the major thrusts of customer-facing principles. There is also a section on creating great employees.
I'm taking a star off because though I took a good number of ideas to implement in my own work, the book's style reminded me of A Passion for Excellence by Tom Peters, which was probably the same style as its predecessor In Search of Excellence. It is a series of chapters broken down by concept and then filled out with several examples of various companies succeeding with those principals. I just find that style a bit dry and grating, for whatever reason. I think it's because you think, 'I get it,' but you can see that there are still a bunch more examples to read through.