This is a dual biography: the story of a man who never stopped learning and the biography of a perilous world whose ills are too big to ignore but too complex to manage quickly or cheaply. Even as Vieira de Mello arranged food deliveries, organized refugee returns, or negotiated with warlords, he pressed his colleagues to join him in grappling with such questions as: When should killers be engaged and when should they be shunned? When is military force justified? How can outsiders play a role in healing broken people and broken places? He did not have the luxury of simply posing these questions; he had to find answers, apply them, and live with the consequences.