Common law is also referred to as “judge-made law” or “case law.” Common law is law that is contained in the opinions of the appellate courts. Statutory law is enacted through legislation. In general, most crimes are defined by statutory law while many aspects of criminal procedure are defined by common law—usually consisting of U. S. Supreme Court decisions that interpret the U. S. Constitution's Bill of Rights.
For example, a defendant, while in custody, must be read his or her Miranda Rights prior to being interrogated. The term Miranda Rights comes from the U.S. Supreme Court case, Miranda v. Arizona, which established that a defendant's incriminating statements cannot be used as evidence against him unless he is advised of the right to remain silent and have legal representation.