Drawing on two decades of research and business experience, Aral goes under the hood of the biggest, most powerful social networks to tackle the critical question of just how much social media actually shapes our choices, for better or worse. Aral shows how the tech behind social media offers the same set of behaviour-influencing levers to both Russian hackers and brand marketers—to everyone who hopes to change the way we think and act—which is why its consequences affect everything from elections to business, dating to health. Along the way, he covers a wide array of topics, including how network effects fuel Twitter’s and Facebook’s massive growth to the neuroscience of how social media affects our brains, the real impact of fake news, the power of social ratings, and the effect of social media on our kids.