Patent litigation is a complex system wherein patent law is refined through interactions among the judicial system’s constituent components—principally, the litigants, district courts, United States Court of Appeals for the Federal Circuit (Federal Circuit), Supreme Court, Patent and Trademark Office (PTO), and Congress’s patent laws. Typically, litigants pore over existing laws—both congressional statutes and judicial opinions—to determine whether to file, defend, or settle a patent suit in a district court. The district court rules on the litigants’ claims. When prompted by a losing litigant, the Federal Circuit—the appellate court designated to hear nearly all appeals of patent cases reviews the district court’s decision. Finally, the Supreme Court might entertain further review if it is convinced that the case is sufficiently worthy. This interaction is not unidirectional. For example, the Supreme Court and the Federal Circuit, in articulating rules of patent law in its decisions, are or ought to be attentive to making it straightforward for the district courts to apply these rules properly. Making sure that patent law develops appropriately in the courts requires attention to each of the principal components of the litigation system and their interactions with one another.