If you want to be good at any art form, you have to master the craft. Artists spend years mastering their craft and then their whole lives working on that craft. The same is true for professional athletes. If you want to practice the art of leadership really well, you have to master the craft of leadership. What is the craft of leadership? The simple answer is that in the same way that woodworking is the craft of working with wood in order to make things and glass blowing is the craft of working with glass to make things, leadership is the craft of working with other humans in order to do something. While we have probably been trained in our primary craft, whether that is in medicine, the arts, engineering, or some other discipline, the craft of interacting with others, the craft of working together is usually taken for granted. It is something we know how to do simply because we are humans and human beings are social animals--we cooperate, collaborate, and compete with each other all the time. We manage to muddle through, sometimes with pretty good results, sometimes with not very good results, but we are not masters because we have not pursued mastery of the craft of interacting with others. This is a "how-to" book for learning the techniques of reflective practice in the action science and action inquiry traditions in order to develop and practice that craft. The book explains how to use various tools, such as the Ladder of Inference, the Learning Pathways Grid, and the Change Immunity Map, for offline reflection and active experimentation in order to develop and practice the craft of leadership.