Once a freewheeling frontier, the Internet is approaching lockdown as we trade freedom for the promise of security in our online lives, Oxford University cyberlaw scholar Jonathan Zittrain says. Viruses, spyware, malware, and spam are driving Internet users away from technologies like Wikipedia, which anyone can modify, toward appliances such as iPods, iPhones, Xboxes, and TiVos, which only their makers can modify. The control that the developers of these “tethered appliances” retain threatens to stifle the innovation that gave rise to the Internet, and it can be turned against us too—to spy on us, sell our secrets, silence dissent, and eliminate choice. Zittrain sounds the alarm in clear, compelling language and maps out a plan that could provide reasonable security without sacrificing what we most want to protect about the Internet.