The U.S. Supreme Court’s 1992 decision in Lucas v. South Carolina Coastal Council was celebrated by libertarian property rights enthusiasts as a landmark decision that would revolutionize interpretation of the Constitution’s takings clause and finally fulfill its potential as a vehicle for deregulation. Over a quarter-century later, the Lucas decision has failed to meet those expectations. A major reason is that Justice Scalia’s opinion created an exception that effectively swallowed the rule that Lucas established. The Lucas case held that land use regulations whose effect on landowners’ property produced a total loss of economic value were per se, categorical takings. However, Justice Scalia qualified the categorical rule by creating an exception if the regulation merely replicated “background principles” of property or nuisance law. His Lucas opinion explained that an examination of background principles was a “logically antecedent inquiry” in takings cases because it defined the nature of the alleged “private property” taken by the regulation. Over the years, courts have interpreted the background principles rule expansively, while the per se taking rule has rarely applied. Background principles, as an inquiry antecedent to takings claims, demand analysis of applicable property and nuisance law because they determine the nature of the “private property” alleged to have been taken. Consequently, this examination is step 1 of any claim for compensation — regardless of whether an alleged physical occupation or appropriation, an economic wipeout, or a regulatory taking subject to judicial balancing. Step 2 — whether there has been a taking requiring government compensation—cannot proceed until a court conducts the initial inquiry into the alleged property right. This article surveys recent background principles cases, building on earlier studies. The survey reveals that courts have continued to recognize common law background principles like the public trust doctrine, the navigation servitude, customary rights, and even burial rights. In addition to common law background principles, courts have found numerous statutory background principles — including public ownership of wildlife and water, zoning, and federal mining regulations. Other cases have rejected some statutes as background principles, including wetland regulations, environmental impact statement requirements, and flood control operations. Background principles are likely to continue to be a dynamic area of property and constitutional takings law for the foreseeable future because the issue will be raised early in every takings case, and the results may be as varied as the states’ interpretation of their property and nuisance laws. Background principles should prove a fruitful source of state court modern interpretations of vintage doctrines like the public trust, customary rights, and public ownership of wildlife and water, even rights to access burial grounds. These cases will likely make takings law a vibrant area of property law for years to come.