Cases in which more than one party is involved in infringing a patent embody one of the most vexing areas of patent law. These multi-party problems become particularly salient when plaintiffs assert socalled method patents, which cover specific" steps," or actions.'In the stream of commerce, manufacturers, distributors, and end users might all participate, to varying degrees, in the infringement of such patents. 2 The manufacturer might design a product whose operation entails performing the claim's steps, the distributor might sell it, and the end user might actually operate the product. Lucent Technologies, Inc. v. Gateway, Inc., a case involving a patent covering the functionality of scheduling appointments using a graphical interface, illustrates this kind of a situation. 3 The infringing steps took place when a Microsoft Outlook user clicked on a time slot in the calendar window and typed in a title-say," Breakfast meeting." 4 But performance of these steps was