What is patentable subject matter under the U.S. Patent Act, 1952 is governed by Section 101. Case law related to this Section has an interesting history. It led to the patenting of living matter, soft-ware inventions, and business methods, all of which were believed to be unpatentable before the courts decided otherwise. Even after decades of litigation involving Section 101, its interpretation is not yet settled. There is no surer way to misread any document than to read it literally . . . . As nearly as we can, we must put ourselves in the place of those who uttered the words, and try to difine how they would have dealt with the unforeseen situation; and, although their words are by far the most decisive evidence of what they would have done, they are by no means final.