The idea of security—from ancient Greece to the War on Terror In The Security Principle, French philosopher Frédéric Gros takes a historical approach to the concept of security, looking at its evolution from the Stoics to the social network. With lucidity and rigour, Gros’s approach is fourfold, looking at security as a mental state, as developed by the Greeks; as an objective situation and absence of all danger, as prevailed in the Middle Ages; as guaranteed by the nation-state and its trio of judiciary, police, and military; and finally biosecurity, control, regulation, and protection in the flux of contemporary society. In this deeply thought-provoking account, Gros’s exploration of security shines a light both on its past meanings and its present uses, exposing the contemporary abuses of security and the pervasiveness of it in everyday life in the Global North.