As a professor of conflict analysis and resolution, I enjoy introducing students to the extraordinary work of peacebuilders, whose undertakings are designed to bring about peaceful social change whether supporting peace negotiations and agreements, shifts in political and economic institutions, or enhanced relationships and cooperation between ethnic, religious and cultural groups. Inevitably I field questions such as ‘How do we know if peacebuilding works?’ ‘How can you measure conflict prevention?’ ‘Can a small NGO really bring about big social changes?’ ‘Is a peacebuilding project successful if it doesn’t prevent violence?’ Building Peace adds its weight to a growing volume of work that takes these questions seriously by providing ‘systematic, valid and reliable documentation of the effects’ of peacebuilding projects from around the world.