These essays assess market liberal or libertarian political theory. They provide insights into the limits of government, develop market-oriented solutions to pressing social problems, and explore some defects in traditional libertarian theory and practice. Some of the essays deal with crucial theoretical issues, asking whether the promotion of citizens’ welfare can serve as the justification for the establishment of government, or inquiring into the constraints on individual behavior that exist in a liberal social order. Some essays explore market liberal or libertarian positions on specific public policy issues, such as affirmative action, ownership of the airwaves, the provision of healthcare, or the regulation of food and drugs. Other essays look at property rights, the morality of profit-making, or the provision of public goods. Still others address libertarianism as a political movement, suggesting ways in which libertarians can reach out to those who do not share their views.