New technology has offered the public the opportunity to witness police use of force far more frequently than in the past - and has brought into sharp focus a number of big questions. Where does police power to use force come from? How have the federal courts ruled on the subject? What sort of guidelines have police departments given their officers, and are they appropriate guidelines? Do the officers follow them? Craig Boylstein draws extensively on data to explore these questions, addressing current controversies, analyzing how force is applied in various contexts and across various...