The principal strength of holdings in these collections is in the breadth and depth of primary source material. Our earliest resources in this category are medieval manuscripts followed by 15th and 16th century printed works, valued not only for their glass-related content but also for the high standards of historical book production which they embody. Among the more outstanding primary source materials from later periods are scientific treatises published in the 17th and 18th centuries; 19th and 20th century designs for glass objects executed by an international roster of artists; production drawings from both American and European glass studios or manufactures; %%batch%% books documenting unique glassmaking recipes; stunningly illustrated pattern books and trade catalogs from the Art Nouveau and Art Deco periods; and a broad range of archival collections from historical and contemporary sources, including the notebooks, personal diaries, and letters of individual artists and glassmakers; the private and public papers generated by galleries, studios, collectors, and organizations; and the working papers and personal libraries of individual researchers.