The analysis of the genre apocalypse published in Semeia 14 (1979) relied on a classificatory approach, which identified core features of the genre, listed features that were typical but not necessary, and distinguished different types of apocalypses. The main difficulty encountered by such an approach is that genres have fuzzy edges. Some works that fit the definition are atypical of the genre, while some that do not have much in common with it. The emergence of prototype theory as a method of analysis is helpful in this regard, and allows for a less rigid kind of classification, without lapsing into the indeterminacy of family resemblances. Genres are recognized on the basis of a few clear exemplars. Other works may resemble them to a greater or lesser extent.