The present volume is the second supplement to the original published in 1951. The plan and scope of the two supplements are essentially the same as for the basic the listing of printed library catalogs, union lists of books and periodicals, descriptions of special collections, surveys of library holdings, calendars of archives and manuscripts, and catalogs of exhibitions. Also included are a number of unpublished bibliographies, chiefly theses and dissertations, since these are usually available in some form of reproduction.