Chapter 4 focuses on how ownership of immovables and movables are transferred (that is, whether registration is not needed, necessary, or creating opposability to third parties), whether registration creates absolutism (public faith principle), whether a real agreement is conceptually separate from a sale contract, and whether an invalid sale contract always leads to the invalidity of a real agreement (non-causa principle), and whether delivery or certain intentions are required to transfer ownership of personal properties or the sale contract itself is sufficient. This is where the traditional idea of legal families is conspicuous. Transfer doctrines involve how notice is given. The choice of registration system demonstrates how states, given path dependence, trade off transaction costs and third-party information costs. Which type of conveyance doctrine regarding immovables is efficient is contingent on factors outside of the law. It is easier to reform conveyance doctrine regarding movables, and lawmakers should provide alternative default rules (“menus”) more frequently and establish clear opt-out procedures (“altering rules”).

Chapter 13 focuses on the accessio and confusio doctrines, traditionally sibling doctrines to the specificatio doctrine. The accessio doctrine includes three types of combinations: immovables and immovables, movables and movables, and movables and immovables. Confusio concerns only mixture of movables. The big picture of these doctrines is that there is little sign of convergence, except perhaps in confusio. From an economic standpoint, it is quite clear when two things should be considered combined (thus the accessio doctrine applies) rather than separable: If (the value of attached thing) > (the value of the two post-separation things combined) + (the cost of separation), the two things should remain combined. The next question is who should own it. The key concern behind my analysis is still to deter opportunistic or careless interference with other’s property.

Chapter 5 analyzes acquisitive prescription, a broader concept than adverse possession, and argues that registration-based acquisitive prescription with title and good-faith requirements can be justified by efficiency under certain conditions—Possession, however, is redundant, and may even give rise to undesirable outcomes. Given that boundary disputes can be left for another doctrine, possession-based acquisitive prescription—no matter whether possessors act in good or bad faith—can hardly be justified on an economic basis in countries with well-functioning registrars if possessors do not have title. The possession-based acquisitive prescription can only be justified in jurisdictions with dysfunctional registrars.

Chapter 3 focuses on the numerus clausus principle and the limited property rights. It first documents that about a quarter of jurisdictions explicitly adopt this principle, while many others do so implicitly. Chapter 3 argues that this principle is generally efficient. Chapter 3 will also show that property forms such as mortgage (called hypothec in civil law) and real easement are extremely popular.

Chapter 8 first provides an overview of the stipulations regarding how things held in tenancy in common (the most common co-ownership form of property around the world) should be administered and sold, as well as co-owner agreements not to partition. Then, Chapter 8 addresses whether the several types of rules lead to underuse or overuse — that is, whether tenancy in common may lead to tragedy of the commons or anticommons. The prevalent doctrine that provides one co-owner with a unilateral power to call for partition avoids a long-term tragedy but underinvestment and underuse of co-owned resources are still likely. This chapter ends with a proposed solution to ameliorate the underinvestment and underuse problems.

Chapter 6 discusses building encroachment, which is a topic closely related to adverse possession—at least in the common law. Chapter 6 documents the three different doctrinal approaches to dealing with encroachment over boundary and focuses on the building encroachment doctrine enacted in 52 jurisdictions. The prompt protest rule and encroachers’ not acting in bad faith are easy to justify economically (though not universally adopted). Encroachers’ good faith is increasingly unlikely given the advance of mapping technology. A two-tier building encroachment doctrine (with safe harbor and sure shipwreck) is best. Even though this doctrine has been used as an example of a put option, it is not, and will be inefficient if treated as such.

Chapter 9 studies access to landlocked land and shows that most jurisdictions aptly use a mixture of ex ante and ex post viewpoints to design their doctrines. This chapter follows American parlance and divides the doctrine into “easements of necessity” and “statutory easements.” They have intuitive appeal: for statutory easements, owners of servient land should be compensated; easements should be necessary; and the location of the passage should cause the least damage to the servient land. As for easements of necessity, the landlocked owners can only gain access to land held by the grantor at the time of the conveyance. The prevalent scheme under statutory easement to solve this legal entanglement is neither the property rule nor the liability rule, but a “hybrid rule,” an unheralded mixture of the property rule and liability rule. Chapter 9 argues that the hybrid rule stipulates that the extent of statutory easements should be set at where the marginal social benefit of prescribed passage sharply declines, and passage locations should be determined following the least damage rule. As for easements of necessity, the limited access rule and the gratuity requirement make economic sense from an ex ante viewpoint.

The Conclusion recapitulates the lessons of the comparative, empirical, and economic analyses and points out future directions that enable us to even better test the grand property theories and understand property legal systems around the word.

Chapter 2 defines efficiency. The efficiency criterion here is cost-benefit analysis, where cost is institution cost (including information and transaction costs) and benefit is what is called “allocative efficiency” in the literature. My efficiency criterion builds on 60 years of law-and-economics research in property law, but I believe that this is the first time that efficiency has been formulated in this way. Chapter 2 positions efficiency as a first-order value, while welfare is a second-order value that includes efficiency and other first-order values such as distribution of wealth. In addition, Chapter 2 introduces the concepts of ex ante viewpoint and the property rule versus the liability rule, both of which will be drawn on in later chapters.

Chapter 11 observes that “finders, keepers” is in fact a minority rule globally. Finders often have to wait for several months to receive any benefit, and often cannot acquire ownership of the found items. Instead, they may receive rewards from the losers or from the state. The current economic analysis of this issue does not map exactly onto the doctrine itself. The better economic justification for the finder doctrine is that providing rewards induces finders not to misappropriate found items or leave them alone.