Abstract
Security in International Relations has undergone profound changes since the end of the Cold War. After the end of bipolarism the system of International Relations has experienced three main variations concerning structure, provision and perception of security. First of all, the international arena must deal with the consequences of the progressive decline of sovereignty and the shifting from a statocetric to a multicentric model of global relations; secondly, non-state actors are emerging as brand-new providers of security in many parts of the world; finally, new representations of security are shaping the social perception of “safety” pointing out the needs to give certainty and protection to single, weak persons as the real target for collective international security produced by responsible states.