This chapter outlines the changing nature of peace-keeping in response to the shift from ‘classical’ interstate warfare, characteristic of the Cold War period, to protracted intrastate conflict. It examines the challenges that have arisen as a result both of the ad hoc evolution of peace-keeping and the complex conflicts which the international community faces. UN peace-keeping1 became the most widely employed means of containing violent conflict and contributing towards its ultimate resolution in the post-Cold War world. Many regional conflicts and most civil wars were suppressed or seen as a reflection of the attenuated US–Soviet confrontation. Throughout this period, conflicts were handled by traditional methods of coercive diplomacy and crisis-management through the superpower rivalry. Consequently, the international community has responded in a different manner to the destructive conflicts found in the post-Cold War world. As a result of evolution of peace-keeping, academics, the military and civilian institutions have attempted to conceptualize and categorize the activities of post-Cold War peace-keeping.