Internet security is a complex and challenging problem. Malicious actors and their associated attack technologies have advanced significantly. Moreover, Internet-enabled platforms such as cyber-physical infrastructures, the mobile Internet, cloud computing, the Internet-of-Things, vehicular networks, and smart-home environments will provide countless new attack vectors for malicious actors. Consequently, advanced security mechanisms and defense methodologies are needed for the protection of traditional Internet systems along with these emerging Internet-enabled platforms. This book introduces algorithms, theories, and supporting frameworks seeking to improve the growing problem of Internet security. The material covered in this book describes (1) distributed Internet security architectures and infrastructures, (2) the design of a modular, adaptive, and integrable framework for distributed Internet security infrastructures, (3) the development of a semantic computing-based solution addressing the fundamental packet classification problem, and (4) the design and analysis of computational intelligence algorithms for advanced cyberattack detection systems.