In this volume, fourteen philosophers, economists and legal scholars and one computer scientist address various facets of the same question: under which conditions (if any) can intellectual property rights be fair? This general question unfolds in a variety of others: What are the parallels and differences between intellectual and real property? Are libertarian theories especially sympathetic to IP rights? Should Rawlsian support copyright? How can a concern for incentives be taken into account by each of the main theories of justice? What's exactly wrong with free-riding, when dealing with non-rival goods? This requires a close examination of a variety of specific issues such as peer-to-peer file sharing, access to vital medicines, the interaction between copyright and freedom of expression, patents on genes, etc. It also involves bringing together state-of-the-art knowledge on legal, economic and technical issues with the most advanced state of our normative theories.