Since the writings of Adam Smith, economists have understood the important role that private property rights play in a well functioning economic system. Without well-defined, enforced, and transferable property rights, the tragedy of the commons is said to result as in the classic case of over-fishing and over-grazing. This book challenges this narrow view of property rights by examining the role of informal constraints imposed by customs and culture. Recognizing that a great deal of human interaction takes place in the absence of individually specified rights, the authors challenge the notion that tragedy is inevitable within the commons.