This series is contained in Boxes 1 and 2 and consists of letters and documents exchanged or shared among members of the Society, as well as between the Society and other organizations. Items are arranged alphabetically by organization or author last name. Though the series spans the periods of 1880 to 1899 and 1908 to 1912, the majority of the items date from the former period. Many materials pertain to issues of the Society's membership, including payments, dues, applications, elections, resignations, solicitations for membership, and appointments of Society members to various positions. Other items include receipts, accounts, announcements of annual dinners and meetings, and acknowledgements from libraries throughout New England and New York State regarding gifts from the Society. Many distinguished individuals from the Society's history are represented in this series, including its first two Presidents, Benjamin D. Silliman and John Winslow, Secretary Thomas S. Moore, Treasurer Charles N. Manchester, and Treasurer Franklin W. Hooper. Other items of interest include those pertaining to the Society's raising of funds toward the creation of a marble bust of Silliman, and those surrounding the financial scandal involving the embezzlement of Society funds by clerk Herbert Owen, which resulted in Treasurer Hooper's resignation.