The literature on inventors has traditionally focused on entrepreneurs who exploited their ideas in their own businesses and on researchers who worked in large firms' R&D laboratories. For most of US history, however, it was as common for inventors to profit from their ideas by selling off or licensing the patent rights. This article traces the different ways in which inventors resolved the information problems involved in marketing their patents. We focus in particular on the patent attorneys who emerged during the last third of the nineteenth century to help inventors find buyers for their intellectual property.