The world is in the midst of a transformation in the nature of work, as smart machines, artificial intelligence, new technologies, and global competition remake how people do their jobs and pursue their careers. The Work Ahead: Machines, Skills, and U.S. Leadership in the Twenty-First Century focuses on how to rebuild the links among work, opportunity, and economic security for all Americans in the face of accelerating change. The United States needs to create new work opportunities, better career paths, and higher incomes for its people, while developing a highly skilled and adaptable workforce. To prosper and to lead, the United States needs to find new ways to meet the workforce challenges of the twenty-first century.