Book excerpt: When does democracy work well, and why? Is democracy the best form of government? These questions are of supreme importance today as the United States seeks to promote its democratic values abroad. Democracy and Knowledge is the first book to look to ancient Athens to explain how and why directly democratic government by the people produces wealth, power, and security. Combining a history of Athens with contemporary theories of collective action and rational choice developed by economists and political scientists, Josiah Ober examines Athenian democracy's unique contribution to the ancient Greek city-state's remarkable success, and demonstrates the valuable lessons Athenian political practices hold for us today. He argues that the key to Athens's success lay in how the city-state managed and organized the aggregation and distribution of knowledge among its citizens. Ober explores the institutional contexts of democratic knowledge management, including the use of social networks for collecting information, publicity for building common knowledge, and open access for lowering transaction costs. He explains why a government's attempt to dam the flow of information makes democracy stumble. Democratic participation and deliberation consume state resources and social energy. Yet as Ober shows, the benefits of a well-designed democracy far outweigh its costs. Understanding how democracy can lead to prosperity and security is among the most pressing political challenges of modern times. Democracy and Knowledge reveals how ancient Greek politics can help us transcend the democratic dilemmas that confront the world today.