In the eighteenth century, life for music librarians must have been much harder than in earlier periods. The enormous increase in production and variety of genres--sacred and secular, manuscript and print, score and parts--demanded new solutions. Did the Enlightenment live up to its name in rationalizing problems such as size-grouping, shelving, uniform binding and marking, and organizing by specialized directories? The need for locational control of this complex mass of material alone must have produced a large number of catalogues, to judge from the surprising number that survive. That fewer catalogues from earlier periods have come down to us, may be the quite natural result of wear and tear, and (ultimately) loss. Also, a smaller total volume of music may have permitted reliance on human memory without formal listing. Furthermore, in certain respects the material was self-indexing, by the church year and the components of the liturgy; and for instrumental music, by the size and character of the group, though unfortunately not always by composer names. In the expanding situation after 1600, opera and its voluminous performance materials may have supplied the critical mass that triggered new thinking about the organization of musical storage. Even a small courtly establishment of the period required not only stage and church music, but a vastly increased production of chamber and concert repertory. How to control this mass? The library finding tool that provided the most effective answer to these problems was the a misnomer that no amount of scholarly protest has been able to correct.(1) These catalogues usually list in staff notation the opening bars of the first violin part, not necessarily the theme of the work, which often appears after conventional opening flourishes. Embarrassingly for scribes, after about 1790, composers do not always score for violins at the beginning, creating the anomaly of thematic rests while other instruments played. A more logical term, incipit catalogue, for some reason never took root in musical usage. With the growing concern for authentication in musicology, researchers always welcome the publication of such a whether just a few manuscript pages interleaved between orchestral parts or a solid facsimile publication such as the Durniz Catalogue, the full title being Freiherr Thaddaus yon Durniz und seine Musikaliensammlung.(2) This title is somewhat misleading, suggesting a fairly extensive monograph. Instead we find two and one-half pages of mainly biographical introduction and fourteen footnotes. This meagre preface, however, does supply useful material, since there is no entry for this aristocratic pianist, bassoonist, and composer in Gerber, Eitner, Riemann, MGG, Baker-Slonimsky, or the New Grove Dictionary. The editor hints at the importance of the Catalogue by noting the composers most frequently represented, including Mozart (74 entries), Pleyel (57), Haydn [J.] (43), Sterkel (37), and Clementi (33). Possibly even more important is the socio-musical documentation implied in this unusually complete record of a highly developed chamber tradition leaning heavily on works with keyboard involvement. Apart from solo sonatas, arrangements of operas (Benda's Medea), reductions of orchestral symphonies, and shorter works--even a Parthia--we find an unusually rich array of combinations: keyboard four hands; keyboard duos with violin, flute, and bassoon; collections for keyboard and voice; keyboard trios and quartets in many different mixtures and re-arrangements of strings and winds; and large representation of keyboard concertos, including a round dozen by the Baron himself and important works of Mozart and Haydn. With the sale in 1859 of Hienhart, the main residential estate, the collection seems to have disappeared entirely. Perhaps RISM will recover some of the most intriguing items, such as a for cemb: Primo e 2do by Schuster, and a possibly unique combination concerto a quattro mani by Bachschmidt, both works with normal eighteenth-century orchestral accompaniment (strings, oboes, horns). …