The future of government arrived four years ago. Government became simpler, it became smarter, and Cass Sunstein was at the centre of it all. Drawing on state-of-the-art work in behavioural psychology and economics, Sunstein, as administrator of the powerful White House Office of Information and Regulatory Affairs (OIRA), quietly helped save the nation billions of dollars while preventing thousands of deaths and countless illnesses and accidents. All this was accomplished in part through the extraordinary power of nudges-low-cost, seemingly modest policies that preserve freedom of choice. In combination with smart, disciplined cost-benefit analysis, nudges are simplifying government and making it far more effective. Twenty-first century insights now inform simplified mortgage and student loan applications, the labelling of food and energy-efficient cars, financial reform, and health care reform. New principles-democratizing data, presenting individuals and businesses with the most salient information, ensuring that the better outcome is the automatic outcome-are transforming government. Countless regulations are being streamlined or eliminated. Transparent review of which rules are working, and which aren't, is becoming the norm. Citing numerous examples from his years in the first term of the Obama Administration, and projecting forward into a data-driven future, Simpler provides a new understanding of how government can work.