1. The Ninth and Tenth Centuries

The earliest theoretical discussions of organum are preserved in the complex of treatises surrounding the Musica Enchiriadis (ca. 900).
These are edited in: Hans Schmid, Musica et Scolica Enchiriadis una cum aliquibus tractatulis adiunctis, Veröffentlichungen der
Musikhistorischen Kommission 3 (Munich: Bayerische Akademie der Wissenschaften, 1981), reviewed by Nancy Phillips in JAMS 36
(1983) 128-42. See also her dissertation: "Musica and Scolica Enchiriadis: the Literary, Theoretical, and Musical Sources," (New York
University, 1984). A facsimile of one of the manuscripts is Paris, Bibliothèque Nationale fonds latin 7211: Analysis, Inventory and Text,
ed. Alma Colk Santosuosso, Publications of mediaeval Musical Manuscripts 18 (Ottawa: Institute of Mediaeval Music, 1991). A recent
article is Charles M. Atkinson, "On the Interpretation of Modi, quos abusive tonos dicimus," Hermeneutics and Medieva Culture ed.
Patric J. Galacher and Helen Damico (Albany: State University f New York Press 1989) 147-61.

English translations: Anonymous (ninth century), Music Handbook/Musica Enchiriadis, transl. Léonie Rosenstiel Colorado College
Music Press Translations 7 (Colorado Springs: Colorado College Music Press, 1967), but like many of the translations in this series, this
one needs to be used with care. Partial translatins of the Musica Enchiriadis in Ruth Halle Rowen, Music Through Sources and
Documents (Englewood Cliffs: Prentice-Hall, 1979) 74-78. Parts of the Scolica Enchiriadis in Oliver Strunk, Source Readings in Music
History (New York: W.W. Norton, 1950) 126-38. These and other organum treatises through Guido are edited with German translations
in Ernst Ludwig Waeltner, Die Lehre von Organum bis zur Mitte des 11. Jahrhunderts 1, Münchener Veröffentlichungen zur
Musikgeschichte 13 (Tutzing: Hans Schneider, 1975).