This Article provides the first major analysis of the very recent en banc decision of the United States Court of Appeals for the Federal Circuit in the now famous Therasense v. Becton Dickinson. The doctrinal issue central to the case is inequitable conduct, a judicially created doctrine developed to punish patent applicants who behave inappropriately during patent prosecution, the ex parte process of patent creation. The core thesis of this Article is that Therasense could have a much more significant, complex, and nuanced impact on the legal infrastructure of American innovation than the opinion for the court appears to appreciate. In view of these complexities, the court may be too sanguine in its expectations for the instrumental effect of its decision, a decision that has the potential to erode some of the core pillars upon which the legal infrastructure of American innovation is built.