The National Stolen Property Act has two major purposes: it helps States prosecute those who steal property and transport it to another State to avoid the jurisdiction of the former State, and it deters theft and the transportation and receipt of stolen property by imposing heavy penalties. Elements of a crime under the Act are discussed in detail, along with relevant case law and defenses. In 1985, the U.S. Supreme Court held that the National Stolen Property Act could not be used to prosecute cases involving the transportation in interstate commerce of goods that infringed pre-existing copyrights. Theft of the intangible elements of a trade secret could probably not be prosecuted under the Act either. 98 footnotes.