The playwright George Bernard Shaw once said "The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." Highly unconventional capitalists and entrepreneurs who are solving some of the world's great economic, social, and environmental problems are, in the process, disrupting existing industries, value chains, and business models, and replacing them with fast-growing markets in all corners of the world. The Power of Unreasonable People argues that leaders and decision-makers can gain insight into the future of market opportunity from the mindset and strategies of this new type of entrepreneur. The book offers an on-the-ground look at social entrepreneurs by identifying a new breed of "unreasonable" entrepreneurs, explaining how their enterprises have been built, exploring the impact of their work on future market risks and opportunities, and finally highlighting lessons for tomorrow's leaders. Incumbents who recognize the value of investing in, partnering with, and learning from these entrepreneurial operations will be better positioned to adapt to the disruption and adopt new business practices. John Elkington is the Founder, Chief Entrepreneur, and Non-Executive Director of the international consultancy SustainAbility. Pamela Hartigan is Managing Director for the Schwab Foundation for Social Entrepreneurship.