Changing how systems work-and who they work for-isn't for the faint of heart. When she launched the world's first stock exchange for social enterprises, Durreen Shahnaz started more than a new financial system; she sparked a movement. Defiant optimism-the stubborn belief that systems that enrich the few can be transformed for the good of the many-requires an indomitable spirit. Shahnaz illuminates what investing in those excluded from networks of power and opportunity requires.