Book excerpt: "Fortna demonstrates that peacekeeping is an extremely effective policy tool, dramatically reducing the risk that war will resume. Moreover, she explains that relatively small and militarily weak consent-based peacekeeping operations are often just as effective as larger, more robust enforcement missions. Fortna examines the causal mechanisms of peacekeeping, paying particular attention to the perspective of the peacekept--the belligerents themselves--on whose decisions the stability of peace depends."--publisher website.