This document discusses the concept of security from different theoretical perspectives. It defines security as freedom from threats to core values like survival, autonomy, political status, and economic welfare. These can be military, political, economic, societal or environmental. Realism views security as a zero-sum game achieved at the expense of others in an anarchic system. Neoliberalism sees institutions as facilitating cooperation by providing information and making commitments credible. Collective economic security, according to Nye, involves deterring threats to economic welfare through interdependence between states.