Considerable revisionary effort is currently being directed toward the systematics of the Fungi Imperfecti and, in particular, toward the classification of the hyphomycetous molds. The classical system of Saccardo, with its emphasis on relatively superficial morphological and ecological characters, provides a classification niche for every known fungus but often is useless in revealing taxonomic relationships based on characters more nearly fundamental than habit, color, or spore septation. A discussion of the requirements of a new, information-rich classification is used to introduce a review of recent systematic revisions based on methods of asexual spore production observed among these fungi.