Possession is a two-thousand-year-old institution, and scholars have debated the concept of possession since the mid-nineteenth century, but modern scholars lack consensus on the definition of possession. Although common-law countries appear to avoid exactly defining possession, civil codes in the European Continent and East Asia take on the challenge. They differ, however, over how possession is and should be delineated. Some countries, such as France and the Netherlands, distinguish possession from detention, whereas others, for example Germany and Taiwan, use the terms “possessors” and “agents in possession.” A few jurisdictions, such as Japan and Korea, consider possession to be a right while others, for instance China, treat it as a fact. Some civil codes, such as those of Germany and Taiwan, simply define possession as actual control, but others, for instance France’s and the Netherlands’, also require specific intents. In short, the concept of possession is either ambiguous or messy. Law and economics has been the dominant legal analytical approach for the past half-century, yet rarely have scholars applied economic analysis to various possession issues. This timely book fills the gap. Leading economic lawyers from both common law and civil law jurisdictions offer their insightful treatment of possession, some at the abstract level, and others toward a specific issue. The book begins with Thomas Merrill’s “Ownership and Possession.” Merrill analyzes the concepts and relations of possession and ownership from the perspective of information costs. Possession imposes low information costs in the world of “strangers,” whereas ownership, harder to prove, requires more information costs in order to conduct impersonal exchange. In the modern world where recording or registration of titles is cheaply available, the reason to continue protecting possession independently of ownership is to expand access to law as a means to enforce property rights.