This Article critically analyzes Bilski v. Kappos, the Supreme Court’s first decision on patentable subject matter since the early 1980s. It shows how the majority’s effort to shoehorn patentable subject matter into a superficial textualist mold obfuscates patentable subject matter boundaries and undermines the patent system on multiple levels. The Article contends that the patentable subject matter pathology cannot be cured without confronting the roots of the disease: the lack of a forthright, principled framework for delineating the boundaries of patentable subject matter. The solution lies in recognizing that patentable subject matter cannot evolve to meet the new challenges of the information age without integrating eighteenth-, nineteenth-, and twentieth-century sources of patentable subject matter law into a flexible and evolving body of common law that is sensitive to history, statutory evolution, constitutional constraints, and an understanding of modern science and technology. This will be particularly important as courts confront the patentability of DNA compounds, diagnostic tests, and unforeseeable information age innovations.