Répertoire International de Littérature Musicale (International Repertory of Music Literature; Internationales Repertorium der Musikliteratur), commonly known by its acronym RILM, is a nonprofit organization that offers digital collections and advanced tools for locating research on all topics related to music.

Although available online already before the advent of the Internet, until the end of the twentieth century the primary medium for distribution for its bibliographic records were printed volumes.

Barry Brook's second report, published in the March 1968 issue of Notes, details the deliberations of the Commission Mixte as it worked to establish the procedures and functioning of RILM.

[8][9] Published since August 1967, it consists of citations of articles, single-author books and collections of essays,[10] bibliographies, catalogues, master's theses and doctoral dissertations,[11][12] Festschriften, films, videos, technical drawings of instruments, facsimile editions, iconographies, commentaries included with critical editions of music, ethnographic recordings, conference proceedings, reviews, web resources as well as over 3500 periodicals that dovetail with the coverage of Répertoire International de la Presse Musicale.

[17] This practice allowed users to find the desired English-language term or the spelling of a personal name by initiating the search from the language most familiar to them.

In the mid-2000s RILM Abstracts began to expand its coverage of Asian publications, with music scholarship published in Chinese periodicals.

[20] Coverage also includes reviews as well as obituaries, editorials, correspondence, advertisements, and news, published from the early twentieth century to the present.

[23][24] Librarian Laurie Sampsel asserts that "cross searching the full text of so many titles yields results impossible (or highly unlikely) to find using the print versions of these encyclopaedias.

"[25] Stephen Henry mentions RME's "ability to provide access to some excellent European resources that might not otherwise be available to libraries with less than comprehensive collections.

"[26] RME’s titles stem from different periods and countries: The earliest, Jean-Jacques Rousseau’s Dictionnaire de musique, was published in 1775.

[28] Among them are Ken Bloom's Broadway, Lol Henderson and Lee Stacey's Encyclopedia of Music in the 20th Century, Peter Matzke et al., Das Gothic- und Dark Wave-Lexikon, and Richard Kostelanetz's Dictionary of the Avant-Gardes.

[30] RME holds important titles for ethnomusicologists, among them The Garland Encyclopedia of World Music and Eileen Southern's Biographical Dictionary of Afro-American and African Musicians, which is the first single comprehensive volume of its kind.

[35] It provides a granular level of detail about each piece, including performing forces, language, multiple clefs or figured bass, and more.

IPM includes the complete contents of Collected Editions, Historical Series & Sets & Monuments of Music: A Bibliography, by George R. Hill and Norris L. Stephens (Berkeley: Fallen Leaf Press, 1997),[36] which, in turn, was based upon Anna H. Heyer's Historical Sets, Collected Editions, and Monuments of Music: A Guide to Their Contents (American Library Association, 1957–1980).

Since 2019 IPM offers new features, among them biographical facts identifying composers, editors, and lyricists; hyperlinks to open-access editions; music incipits for works that are otherwise difficult to distinguish from each other; easy toggling between collections and the individual works contained therein; and expanded search filters to enable refined searching by place and date of publication, document type, genre, and language of text.

[38] While building on the previous efforts, the volume stays true to Brook's original vision while expanding upon it as well: it covers more than 130 years of conference proceedings and has a worldwide scope, though Western Europe remains in focus.

[47] MGG Online is based on the second edition of Die Musik in Geschichte und Gegenwart, but it includes continuous updates, revisions, and additions.