Property rights are social definitions; they exist as long as the society is willing to enforce them. If enforcement is missing, they cease to exist. The reasons for changes might be market conditions, popular sentiments, scientific knowledge, new technologies, lobbying, or legal battles. Biotechnologies are already having profound effects on how we organize property rights for natural resources. Resource rights change as our understandings and sentiments change. This paper presents a general overview of property rights in natural resources, with particular reference to water and land and emphasizing that rights are what a society is willing to grant and enforce. If companies, individuals, groups, or the state are not managing and stewarding resources in sustainable ways, their authority should be challenged. Rights are social inventions, and society can abrogate them.