Information technologies facilitate human activities, including communication, commerce, travel, study, work, voting, and policy dissemination. Cyberspace is no longer a place that exists on the fringe of society. We live in cyberspace, and it seems every activity has a paired terminology starting with e-or cyber-, such as cyber crime, cyber attack, cyber thieves, and e-commerce. As with our physical world, we beneƒt and su®er from activities conducted in cyberspace. Cyberinfrastructures may provide us with access to faster and more convenient modes of communication; likewise, we can su®er from cyber crimes and cyber warfare. In Chapters 3 through 8, we have mentioned many cyber protection techniques to combat malicious cyber activities. However, we cannot cover all levels of cyber attacks and prevention, as the area is vast, complex, and constantly growing. To broaden readers’ views of cyberspace in the years ahead, we summarize the emerging challenges in cybersecurity, focusing on cyber threats, network monitoring and privacy protection, and network intrusion detection.