Many books have charted the use and misuse of social media, but this is one of the most comprehensive and up to date. It comes after a shocking few years in which the abuse of the Internet has had profound political consequences. Belligerents now prepare for Twitter wars at the same time as conventional ones. Activists understand the subversive potential of online campaigns, but so do governments that seek to stifle them. The Chinese government has built the most extensive mechanisms to prevent free expression and weed out dissent, showing the way forward for authoritarian states everywhere. Meanwhile, the main online platforms—Facebook, Google, and Twitter—have come to realize how their creations have been used to stir up hate and spread false stories, and they are belatedly wrestling with ways to curb the worst offences. Singer and Brooking explain not only how this new information environment developed but also why our attitudes and behaviors are so susceptible to manipulation.