A hurricane strikes a city; terrorists attack a nation; global warming threatens the environment--such problems are too large for any one authority to solve alone. Our increasingly globalized and interconnected world calls for a new type of tri-sector leadership in which business, government and nonprofits work together in a state of permanent negotiation. To be effective, tomorrow's leaders will need to reach across national and sector divisions to form a collaborative "megacommunity."

Based on interviews with over 100 leaders from around the world including Bill Clinton, Henry...