Book excerpt: The hypothesis of this handbook is that you don't need to understand the full extent of Service Design to improve the user and customer experience. You don't need to understand all the theory to create great services.That's why each principle in this handbook is summarized in a simple rule of thumb. These simple rules of thumb should be enough for smart readers. You might find, under each principle, a little story, an example, or a study. This additional content can help you turn this principle into action.