When the World Outlawed War. David Swanson

This is a masterful account of how people in the United States and around the world worked to abolish war as a legitimate act of state policy and won in 1928, outlawing war with a treaty that is still on the books. Swanson's account of the successful work of those who came before us to insist that war be outlawed points us toward new ways of thinking about both war and political activism.