This sharply focused study of social relations in nineteenth-century Puerto Rico examines interpersonal violence and police and judicial intervention. Cubano Iguina offers a revisionist perspective on daily life and law enforcement under Spanish colonial rule in the midst of socioeconomic and political changes such as growing agrarian exports, escalating violence, women's participation in the job market, and increasing police and judicial controls. Drawing on extensive research with archival legal records, the author conveys the slippery and multidimensional nature of social and individual behavior, showing that the perpetrators' gender and class significantly affected the application of laws on the island. Cubano Iguina stresses participation by the common people in demanding state-administrated justice to contain violence - particularly intense among young male workers - and in developing strategies to successfully cope with the disciplinary actions of the police and judicial establishment. Nineteenth-century Creole political elites, interested in developing a strong popular base, developed ways to converge with the common people. The author argues that this alliance with state institutions contributed to a sense of belonging within the Spanish legal framework and permitted the successful combined action of colonialism and modern law. Challenging conventional interpretations of Spanish nineteenth-century colonialism, Cubano Iguina shows the importance of emerging forms of modern law for understanding its persistence and function in Puerto Rico.