The disparity between rich and poor countries is the most serious, intractable problem facing the world today. The chronic poverty of many nations affects more than the citizens and economies of those nations; it threatens global stability as the pressures of immigration become unsustainable and rogue nations seek power and influence through extreme political and terrorist acts. To address this tenacious poverty, a vast array of international institutions has pumped billions of dollars into these nations in recent decades, yet despite this infusion of capital and attention, roughly five billion of the world's six billion people continue to live in poor countries. What isn't working? And how can we fix it? The Power of Productivity provides powerful and controversial answers to these questions. William W. Lewis, the director emeritus of the McKinsey Global Institute, here draws on extensive microeconomic studies of thirteen nations over twelve years -- conducted by the Institute it...