This chapter begins by tracing the development of comparative criminology. Then, the chapter covers the actual conduct of comparative criminological research, explaining the necessary preparatory work, and the problems associated with empirical research in this area. Next, there is a discussion of major theories that have been tested by comparative methods, and the benefit of this type of research. The chapter concludes with a review of the goals of comparative criminology, which include learning from other countries’ experiences, developing international strategies to deal with crime, and potential problems that comparative criminologists and the international community will face in the twenty-first century.