A body of rules and statutes that defines conduct prohibited by the government because it threatens and harms public safety and welfare and that establishes punishment to be imposed for the commission of such acts. The term criminal law generally refers to substantive criminal laws. Substantive criminal laws define crimes and may establish punishments. In contrast, Criminal Procedure describes the process through which the criminal laws are enforced. For example, the law prohibiting murder is a substantive criminal law. The manner in which government enforces this substantive law—through the gathering of evidence and prosecution—is generally considered a procedural matter. Crimes are usually categorized as felonies or misdemeanors based on their nature and the maximum punishment that can be imposed.