Chapter 1 makes use of two empirical approaches. Its first part uses property law from 136 jurisdictions in an unsupervised machine-learning method (hierarchical clustering) that divide these jurisdictions into 10 legal families. Unlike the traditional wisdom that highlights the difference between common law and civil law, this chapter finds that, in terms of property doctrines, a trichotomy better describes the legal systems: one big group is jurisdictions affected by French property law; another big group is composed of jurisdictions that follow or resemble German property law; and the final group contains common-law jurisdictions, Nordic countries, and a number of socialist jurisdictions. The second part of Chapter 1 re-combines 156 jurisdictions into 149 countries, and computes the correlation coefficients among each country pair, to show dyadic similarities in property law.