A heterogeneous network is a network which connects computers and other devices with different operating systems, protocols, or access technologies. By definition, managing heterogenous networks is more difficult that homogenous networks. Confidentiality, integrity, availability (CIA) remain the foundation of security. This book sheds light upon security threats, defenses, and remediation on various networking and data processing domains, including wired networks, wireless networks, mobile ad-hoc networks, wireless sensor networks, and social networks through the prisms of confidentiality, integrity, availability, authentication, and access control.