This edited book presents a timely review of the fundamentals, latest developments and diverse applications of nature-inspired algorithms in cyber security and resiliency. Topics include bio-inspired collaboration and cyber security; immune-based defense and resiliency; bio-inspired security and resiliency of network traffic; nature inspired machine learning approach for cyber security; nature-inspired algorithms in A.I. for malicious activity detection; DNA-inspired characterization and detection of novel social Twitter spambots; nature-inspired approaches for social network security; bio-inspired cyber-security for smart grid; nature-inspired cryptography and cryptanalysis, and more.