Xiaoxing Xi was wrongly ensnared in an espionage crackdown. He describes what can be done to make sure it doesn't happen again.

In his new book, Thomas Rid explores the opportunities and challenges that cyberspace creates for those who use violence for political purposes.

Author Thomas Rid says he "can't see a good reason why an innovation that has never injured or killed a single human being — cyber-attacks — should prompt us to rethink the notion of war."