Bass's work is distinguished not only by its brevity and accuracy, but by an entirely original feature, in respect to which he had no predecessor, and almost no successor; namely, a classification of the entire Jewish literature, as far as he knew it. He divides the whole into two chief groups, Biblical and post-Biblical, and each group again into ten subdivisions. Thus, dictionaries, grammars, and translations form a subdivision of the Biblical group; while Talmud commentaries and novellæ are included in the Talmudic group. Although this classification is still very superficial and primitive, it indicates its author's wide knowledge and astonishing range of reading. In addition to the list and classification of the books, Bass gives an alphabetical index of authors, including one of the Tannaim, Amoraim, Saboraim, and Geonim