Biblical studies has traditionally worked with a classificatory or definitional approach to genre. Recent scholarship in genre studies, however, has pointed out the shortcomings of a classificatory system. Among the different theories about genre that are current in genre studies, prototype theory, derived from advances in cognitive science, offers the possibility for thinking differently about genre as a classificatory tool and about what questions we want considerations of genre to answer. Rather than listing necessary features, prototype theory focuses on the way that humans categorize through the use of prototypical exemplars that reflect an idealized cognitive model of a category. Within this approach, genres have indeterminate boundaries and can be extended to include marginal or atypical examples. This paper takes up the categories of apocalyptic and wisdom as examples of how prototype theory can be used to describe a genre, to provide a more effective way to accommodate what are usually thought of as problematic cases, and to think about the generic relations of texts to one another.