Book excerpt: There have been a number of important developments in U.S. intellectual property law since the second edition of Understanding Intellectual Property Law was published. Foremost among them was the adoption, in September 2011, of the America Invents Act, the most significant change to U.S. patent law since the 1952 Patent Act. Coverage of the new Act includes: (1) the first inventor to file system and its effects on the definition of prior art; (2) the new derivation proceedings, replacing the current system of interferences, which allows a patent owner to challenge an earlier filed patent for derivation from the subsequent patent; (3) the prior commercial use defense; (4) the new procedures for inter partes review; (5) the new procedure for post-grant review; (6) the new rules for improper patent marking: (7) changes to the treatment of tax method patents; (8) the new rules pertaining to the best mode requirement; and (9) changes to the rules of jurisdiction. The Supreme Court has been unusually active in reviewing intellectual property cases during the past four years. During that period, it has reviewed and decided 15 patent cases (including three cases on patentable subject matter), four copyright cases, and four trademark or false advertising cases. In addition, the federal Courts of Appeals have decided more than 750 patent cases, 250 copyright cases, and 400 trademark and false advertising cases during that time. Understanding Intellectual Property Law, 3rd Edition covers all of the intellectual property areas and issues likely to be addressed in an intellectual property survey course. Chapter 1 provides a comprehensive introduction.