The U.S. Patent Act of 1952 simplified and clarified language and arrangement, and eliminated obsolete and redundant provisions in existing U.S. patent law. It also effected substantive changes. The major substantive changes were the incorporation of the requirement for invention and the judicial doctrine of contributory infringement in 35 U.S.C. §§103 and 271, respectively. Subject to numerous amendments over the years, the Act originally divided the patent law into three parts. A later amendment added