Retired four-star general Stan McChrystal has lived a life associated with the deadly risks of combat; he has seen how individuals and organizations, too often and to great cost, fail to mitigate risk. Why? Because they focus on the probability of something happening instead of the interface by which it can be managed. In Risk, McChrystal offers a new system of responding to risk, through ten dimensions of control we can adjust at any given time including: diversity, adaptability, communication, technology, and leadership. By monitoring these controls, we can anticipate, identify, analyze, and act when things do not go as planned. Drawing on compelling examples ranging from military history to the business world, and offering practical exercises, McChrystal illustrates how these ten factors are almost always in effect, and how by considering them, individuals and organizations can exert mastery over risk.