"The International Inventory of Musical Sources - Répertoire International des Sources Musicales (RISM) - is an international, non-profit organization which aims for comprehensive documentation of extant musical sources worldwide. These primary sources are manuscripts or printed music, writings on music theory, and libretti. They are housed in libraries, archives, monasteries, schools and private collections.
The organization, founded in Paris in 1952, is the largest and only global operation that documents written musical sources. RISM records what exists and where it can be found. As a result, musical traditions are protected through cataloguing in a comprehensive inventory while also being made available to musicologists and musicians. Such work is thus not an end in itself, but leads directly to practical applications.
The RISM publications represent RISM's activities that began in 1952 and continue to the present day. The online catalog is the focus of RISM's current activities and is freely available online. Series A documents musical sources in two parts: printed music (A/I) and music manuscripts (A/II). Series B is designed to cover specific categories of repertory. Series A and B are supplemented by Series C, the Directory of Music Research Libraries. Special volumes have also been published on the Tenorlied and RISM library sigla (now available as an online database"