This article details an open card sort study administered to undergraduate students, graduate students, and librarians at the University of Colorado at Boulder in order to reveal perceptions of library research guides. The study identifies user group preferences for organization and content of research guides, as well as themes emerging from the collected study data that contrast librarian and user mental models. Interested librarians will gain insights into student perceptions and use of research guides in academic libraries today as well as recommendations for guide design. (Contains 33 notes and 9 tables.)