Introduction In addition to nation-state players, the cyber world is also filled with well-organized criminal groups, independent terrorist groups, and "just for fun" hackers of all stripes. Each offers a particular kind of threat that calls for a complex, varied response. Since the potential threat is a natural part of the internet and hence cannot be completely erased, we refer to the issue as embedded. In traditional warfare, governments have to spend considerable financial and personnel resources on every front—land, air, and sea—but in cyberspace, a single person may wipe out an entire nation. Nuclear weapons need a lot of work to construct, whereas cyber weapons may demonstrate immense harm without costing a dime. Regarding national security, cyber threats have the capacity to endanger the integrity of crucial infrastructure, disrupt the financial system, permit the theft of intellectual property and trade secrets, and deteriorate ties between the government and its...