This special issue provides an introduction to cyberphysical security of networked control systems (NCSs) and summarizes recent progress in applying fundamentals of systems theory and decision sciences to this new and increasingly promising area. NCS applications range from large-scale industrial applications to critical infrastructures such as water, transportation, and electricity networks. The security of NCSs naturally depends on the integration of cyber and physical dynamics and on different ways in which they are affected by the actions of human decision makers. Thus, problems in this area lie at the intersection of control systems and computer security. The six articles that constitute this special issue approach cyberphysical security from a variety of perspectives, including control theory, optimization, and game theory. They cover a range of topics such as models of attack and defense, risk assessment, his special issue provides an introduction to cyberphysical security of networked control systems (NCSs) and summarizes recent progress in applying fundamentals of systems theory and decision sciences to this new and increasingly promising area. NCS applications range from large-scale industrial applications to critical infrastructures such as water, transportation, and electricity networks. The security of NCSs naturally depends on the integration of cyber and physical dynamics and on different ways in which they are affected by the actions of human decision makers. Thus, problems in this area lie at the intersection of control systems and computer security. The six articles that constitute this special issue approach cyberphysical security from a variety of perspectives, including control theory, optimization, and game theory. They cover a range of topics such as models of attack and defense, risk assessment,attack detection and identification, and secure control design.A common theme among these contributions is an emphasis on the development of a principled approach to cyberphysical security of NCS.