Patent eligibility under 35 U.S.C. § 101 should be a straightforward threshold question: any “new and useful process, machine, manufacture, or composition of matter” is eligible for protection. Yet over time, this once-clear principle has become anything but.
Although the statute itself has remained unchanged for two centuries, its interpretation has evolved dramatically through judicial decisions. And it is this common law precedent that has shaped the approach to the determination of patent subject matter eligibility.



