General principles of the criminal law occupy a very special place within the edifice of criminal justice, supposedly providing coherence to what is sometimes the haphazard development of the criminal law. Such principles are often thought to be inherent to criminal justice, and are sometimes described as "fundamental." Their connection to human rights and civil liberties is strong. Most of the general principles studied here will be substantive criminal law principles but the right to a fair trial as a procedural right could also be considered a general principle. General principles are rarely codified, rather they have emerged over time through the case law and the doctrinal writings of scholars, occasionally even receiving constitutional sanction. The globalization of criminal justice has precipitated a move to compare and codify these principles and promote them internationally, if only for the purposes of international criminal justice.
General principles of the criminal law constitute the very backbone of liberal criminal law. They are strongly associated with notions such as the rule of law and the protection of human rights. Although the interpretation of such principles may vary from one jurisdiction and tradition to another, there is a solid common basis for their existence, as evidenced in their recognition in diverse international instruments. However, the strict application of the legality principle has at times been contested and it tends to mean slightly different things in case or statute law based jurisdictions.