No small number of books laud and record the heroic actions of those at war. But the peacekeepers? Who tells their stories?

At the beginning of the 1990s, the world exited the cold war and entered an era of great promise for peace and security. Guided by an invigorated United Nations, the international community set out to end conflicts that had flared into vicious civil wars and to unconditionally champion human rights and hold abusers responsible. The stage seemed set for greatness. Today that optimism is shattered. The failure of international engagement in conflict areas ranging from...