Advice for librarians' professional development sometimes includes encouragement to attend classes, but the benefits for STEM librarians have not been well defined. This article describes a study in which engineering librarians at the University of Vermont and Montana Tech of the University of Montana observed class sessions across first-year engineering programs. The study provided numerous insights into the orientational design of these programs, the scope of the curriculum, building relationships with different groups, the importance of relating instruction to professional success, opportunities for integrating library services, and the ability of non-expert librarians to support STEM programs. This article also provides suggested best practices for an observational project of this kind.