promotion of "the Progress of Science and the useful Arts" : Article 1, section 8 United States Constitution: Congress shall have Power [. . .] To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries; . . . Statute Section 101 of title 35, United States Code, provides: Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title. However, there are restrictions on subject matter eligibility under Section 101 and in general the line between what is deemed patent eligible under Section 101 and what is ineligible changes is, as discussed below, a matter of ongoing judicial activity. History In the late 1960s and early 1970s, the US Patent Office (as it was then called; the name was later changed to the US Patent and Trademark Office [PTO or USPTO]) and the United States Court of Customs and Patent Appeals (CCPA) were at odds over the patent-eligibility of technical advances whose departure from the prior art was only in the use of a software algorithm. The Office rejected such claims and declined to patent them, but the CCPA repeatedly reversed the Office's rulings and ordered the issuance of patents. The Office's position was hampered during the 1960s by the uncertainty over whether the Supreme Court could review decisions of the CCPA, because it was unclear whether it was an Article I or Article III court. That question was resolved, however, in Brenner v. Manson, in which the Court held the CCPA an Article III court and that there was certiorari jurisdiction to review CCPA decisions. The Manson decision also began a string of decisions in which the Supreme Court reversed decisions of the CCPA, and then those of its successor court the United States Court of Appeals for the Federal Circuit (CAFC), which had reversed decisions of the Patent Office or PTO denying a patent to an applicant. Benson case In the first of the Supreme Court's computer software decisions (the "patent-eligibility trilogy"), Gottschalk v. Benson, the Court reversed the CCPA's reversal of a Patent Office decision, thus denying a patent on an algorithm for converting binary-coded decimal numbers into pure binary numbers. In so ruling, the