Crime is a large topic. So too is law. The relationship of crime to law and of both to the society affected by harm done to it raises numerous issues for the lawyer, the historian and the sociologist. Crime is a moral and social, as well as a legal, problem. It therefore attracts the attention not only of legislators, the police, the courts and judges but also of modern film makers and novelists, drawn to an ever-present implied conflict between good and evil. The popularity of modern fiction on detectives in the ancient Roman world, Stephen Saylor's Gordianus the Finder and Lindsey Davis's M. Didius Falco to name but two, testifies to the abiding fascination of the figure of the detective, given extra appeal by his location in the exotic and safely distant antique world.

This book is about how the Romans thought about and discussed offences against the community, who formulated the rules and conventions about crime and how they worked. It is not therefore a manual of criminal law, and discussion is not confined to legal writers, although the ancient jurists, or legal interpreters, are extensively represented. Choice of themes has been, inevitably, selective. One is the impact of legal traditionalism on how crime was discussed and dealt with; a tension existed between legal convention and social values, which affected the ability of the discourse – though not of the judicial system – to adapt to changing perceptions of what crime was.