As the Internet grows more sophisticated, it is creating new threats to democracy. Social media companies such as Facebook can sort us ever more efficiently into groups of the like-minded, creating echo chambers that amplify our views. It's no accident that on some occasions, people of different political views cannot even understand one another. It's also no surprise that terrorist groups have been able to exploit social media to deadly effect. Welcome to the age of #Republic.

In this revealing book, New York Times bestselling author Cass Sunstein shows how today's Internet is driving political fragmentation, polarization, and even extremism--and what can be done about it. He proposes practical and legal changes to make the Internet friendlier to democratic deliberation, showing that #Republic need not be an ironic term. Rather, it can be a rallying cry for the kind of democracy that citizens of diverse societies need most.