An information system is not merely a container for documents; through the ways that resources are selected, organized, and made available to users, information systems themselves work as expressive media, enabling the communication of a specific point of view on the collected materials. By analyzing information systems themselves as documents, we can better understand how information systems communicate these perspectives more and less persuasively, and we can use this understanding to facilitate the design of information systems for communicative purposes. This study examines one communicative mechanism available to information systems: the selective adaptation of genre conventions. Using theories of genre developed in rhetoric, composition, and applied linguistics, I show how two systems for organizing information, the Prelinger Library and the Warburg Institute classification, exhibit deviations from typical genre conventions for libraries, and I show how these deviations work as rhetorical tools to facilitate effective communication. I then demonstrate, using the creation of a prototype, how this understanding of genre as a communicative mechanism for information systems might be translated into the design context. By creating designs that incorporate an enhanced conceptual grasp of genre and other rhetorical properties of information systems, we can facilitate the construction of information systems that systematically and purposefully communicate original, creative points of view regarding their assembled collections, and so enable learning, discovery, and critical engagement for users.