The award-winning Historic American Sheet Music Project of the Duke Libraries Digital Collections provides access to images of more than three thousand pieces of early American sheet music. Almost all of this music is popular vocal music intended for voice with piano accompaniment, and virtually none belongs to the genres of classical or concert music, which are also richly represented in the collections of the Duke Libraries. The Classical String Quartet, 1770-1840, begins to explore this area, and makes available the contents of about forty collections from the period when the string quartet was at its peak, when the works of the Viennese masters for the genre were created, many of them unavailable previously in any form since their original publication. Of particular interest are the various arrangements of operas for string quartet, including Joseph and his Brothers by Méhul, and the famous Magic Flute of Mozart. This resource will be highly valuable to scholars of the period, providing primary sources for study, and to string quartets, with a wealth of new repertoire.