“When a large number of manuscripts of various epochs and from different countries agree in the version of a chant, it may be affirmed that those manuscripts undoubtedly give us the phrase of St. Gregory.” (Dom Guéranger, Institutions liturgiques)

“Never is there one result among many chances.  Error should have been varied . . . .  Whatever is found to be one and the same among many is not an error but a tradition.” (Tertullian)

Franco Ackermans - melodic restoration

Prof. Nino Albarosa (1933–2023) - musicologist known for writings and recordings

Fr. Luigi Agustoni (1917–2004) - semiology, melodic restoration, Einführung in die Interpretation des Gregorianischen Chorals, recordings with Nova Schola Gregoriana

Michael Anderl (b. 1980) - melodic restoration

Prof. Willi Apel (1893–1988) - musicologist, author of the book titled Gregorian Chant

Terence Bailey (b. 1937) - translator of the Commemoratio Brevis

Fr. Roman Bannwart, O.S.B. (1919–2010) - longtime choirmaster of Einsiedeln Abbey, directed fine recordings with the monks and other ensembles

Adam Bartlett - accentualism, Illuminare score editor, Simple English Propers

Br. Gregor Baumhof (b. 1948) - Graduale Duplex

Prof. Inga Behrendt (b. 1978) - melodic restoration

Dr. Mary Berry, CBE (1917–2008; formerly Mother Thomas More) - semiology

Olivier Berten - GregoBase

Dr. Dirk van Betteray (b. 1969) - study of liquescence

Dr. Jan van Biezen (1927–2021) - mensuralism/proportionalism, Rhythm, Meter and Tempo in Gregorian Chant

Marie-Claire Billecocq († 2020) - Graduale Triplex

R. John Blackley (b. 1936) - mensuralism/proportionalism, Rhythm in Western Sacred Music Before the Mid-Twelfth Century and the Historical Importance of Proportional-Rhythm Chant

Benjamin Bloomfield - online tools for GABC notation

Franz Caiter - critic of the Graduale Novum

Dom Eugène Cardine, O.S.B. (1905–88) - Gregorian Semiology, “new Solesmes" style

Robert Carroll (b. 1927) - old Solesmes method, chironomy

Richard Chonak - run.gregoriochant.org engraver

Fr. Bernard Christman - comparison of Solesmes method and mensuralism or proportional rhythm

Dom Jean Claire, O.S.B. (1920–2006) - “new Solesmes" style

Marie-Noël Colette (b. 1939) - musicologist and paleographer, virtuosic semiological recordings

Dr. Richard Crocker (1927–2021)  - semiology, recordings

Dom Antoine Dechevrens, O.S.B. (1840–1912) - mensuralism, meter in chant

Canon G. [given as E. in some sources] Delorme - musicologist and paleographer

Henri (1830–1917) & Jules (1828–1911) Desclée - founders of Desclée & Co. publishers based in Tournai, Belgium

Prof. László Dobszay (1935–2011) - musicologist, semiology, recordings

Fr. Hubert Dopf, S.J. (1921–2015) - recordings with Vienna Hofburgkapelle Schola

Dr. Christian Dostal (b. 1967) - coeditor of the Graduale Novum

Dom Paolo Ferretti, O.S.B. (1866–1938) - musicologist

Fr. Rupert Fischer, O.S.B. (1939–2001) - Graduale Triplex, Offertoriale Triplex, melodic restoration

Dr. Oskar Fleischer (1856–1933) - musicologist

Prof. Constantin Floros (b. 1930) - The Origins of Western Notation (Einführung in die Neumenkunde)

Dr. Robert Fowells - translator of Cardine's Gregorian Semiology, author of Chant Made Simple

Dom Joseph Gajard, O.S.B. (1885–1972) - longtime choirmaster of Solesmes, successor to Mocquereau's approach

Dominique Gatté - Musicologie Médiévale website, Neumz project, 2024 identification of a missing page from Laon 239

Canon Augustin-Mathurin Gontier (1802–81) - probable originator of the nuance theory, i.e., the interpretation of long notes as variable agogic nuances rather than doubling of the short note value

Prof. Johannes Berchmans Göschl (b. 1941; formerly Fr., O.S.B.) - semiology, melodic restoration, Einführung in die Interpretation des Gregorianischen Chorals, recordings, coeditor of the Graduale Novum

Dom Prosper Guéranger, O.S.B. (1805–75) - founding abbot of Solesmes, fostered the study of chant manuscripts

Chris Hakkennes (1916–2003) - Graduale Lagal

Fr. Michael Hermesdorff (1833–85) - musicologist and paleographer, duplex edition

Dom René-Jean Hesbert, O.S.B. (1899–1983) - Antiphonale Missarum Sextuplex

Prof. David Hiley (b. 1947) - musicologist

Andrew Hinkley - digital transcription of chants (GregoBase)

Georges Houdard (1860–1913) - mensuralism, most neumes/syllables of equal length regardless of number of notes

Bernhard Huber - melodic restoration

Michel Huglo (1921–2012) - musicologist

Ewald Jammers (1897–1981) - musicologist

Dom Jules Jeannin, O.S.B. (1866–1933) - mensuralism/proportionalism

Dr. Peter Jeffery - review of new Solesmes editions, ethnomusicology

Dom Dominic Johner, O.S.B. - commentary on the Proper of the Mass

Prof. Godehard Joppich (b. 1932–2024; formerly Fr., O.S.B.) - semiology, melodic restoration, recordings

Xaver Kainzbauer - semiology, melodic restoration, digitalization of manuscript images, Antiphonale Synopticum, Graduale Authenticum, and Graduale Synopticum

Dr. Dirk van Kampen - article espousing semi-mensuralist interpretation

Fr. Columba Kelly, O.S.B. (1930–2018) - semiology, accentualism, English chants

Marek Klein (b. 1969) - recordings, duplex editions

Prof. Stefan Klöckner (b. 1958; formerly Deacon) - Handbuch Gregorianik: Einführung in Geschichte, Theorie und Praxis des Gregorianischen Chorals

Sr. Liobgid Koch, O.S.B. - melodic restoration

Prof. Josef Kohlhäufl (b. 1936) - melodic restoration, recordings

Prof. Debra Lacoste - Cantus database

Fr. Louis Lambillotte, S.J. (1796–1855) - musicologist and paleographer

Fr. Anselmo Lentini, O.S.B. (1901–89) - Liber Hymnarius

Dr. Kenneth Levy (1927–2013) - musicologist, Gregorian Chant and the Carolingians

Alessandro De Lillo - Supplementum ad Graduale Romanum

Geert Maessen - Fluxus notation

Dr. Rebecca Maloy - musicologist, Inside the Offertory

Dr. Timothy J. McGee (b. 1936) - musicologist, The Sound of Medieval Song: Ornamentation and Vocal Style according to the Treatises

Dr. James McKinnon (1932–99) - musicologist, The Advent Project

Dom André Mocquereau, O.S.B. (1849–1930) - Paléographie musicale, Vatican edition, Solesmes method

Dom Gregory Murray, O.S.B. (1905–92) - mensuralism/proportionalism, Gregorian Chant according to the Manuscripts

Royce Nickel - Graduale Renovatum

Jeff Ostrowski (b. 1981) - Corpus Christi Watershed website, rhythm of the Vatican edition

Karl Ott - Offertoriale

Marcel Pérès (b. 1956) - recordings, Old Roman chant

Jacques Perriere - gregorianbooks.com website

Damien Poisblaud (b. 1961) - recordings

Dom Joseph Pothier, O.S.B. (1835–1923) - Vatican edition

Br. Cornelius Pouderoijen, O.S.B. (b. 1950) - coeditor of the Graduale Novum

Prof. Franz Karl Praßl (b. 1954) - coeditor of the Graduale Novum

Friedrich Pustet (1798–1882) - publisher based in Regensburg (Ratisbon), Germany

Prof. Fulvio Rampi (b. 1954) - recordings, chironomy

Prof. Susan Rankin - Writing Sounds in Carolingian Europe

John Rayburn - Gregorian Chant: A History of the Controversy Concerning Its Rhythm

Prof. Luca Ricossa (b. 1960) - mensuralism/proportionalism, Abrosian and Old Roman chant

Prof. Hugo Riemann (1849–1919) - musicologist

Kevin M. Rooney - translator of Van Biezen's Rhythm, Meter and Tempo in Gregorian Chant

Fr. Anthony Ruff, O.S.B. (b. 1963) - semiology

Prof. Heinrich Rumphorst (b. 1934) - melodic restoration, coeditor of the Graduale Novum

Daniel Saulnier (1954–2023; formerly Dom, O.S.B.) - Gregorian Chant: A Guide to the History and Liturgy,  The Gregorian Modes

Dr. Edward Schaefer - semiology, Antiphonale Duplex

Alexander Schweitzer (b. 1964) - melodic restoration

Fr. Joseph Smits van Waesberghe, S.J. (1901–86) - musicologist

Prof. Bruno Stäblein (1895–1978) - rhythm of hymns

Anton Stingl jun. (b. 1940) - Graduale Restitutum, Offertoriale Restitutum

Dom Gregory Suñol, O.S.B. - old Solesmes method, pedagogy

Msgr. Alberto Turco (b. 1937) - Liber Gradualis, recordings with Nova Schola Gregoriana

Dominique Vellard (b. 1953) - virtuosic semiological recordings

Fr. Jan Vollaerts, S.J. (1901–56) - mensuralism/proportionalism, Rhythmic Proportions in Early Medieval Ecclesiastical Chant

Prof. Peter Wagner (1865–1931) - Einführung in die Gregorianischen Melodien: Ein Handbuch der Choralwissenschaft, Vatican commission, mensuralism/proportionalism

Georg Wais - collaborator with Kainzbauer on the Antiphonale Synopticum,Graduale Authenticum, and Graduale Synopticum

Justine Ward (1879–1975) - old Solesmes method, pedagogy

Stephan Zippe (b. 1972) - melodic restoration, coeditor of the Graduale Novum

Note: This list includes people associated with the restoration of Gregorian chant who have published, edited, translated, recorded, or developed websites about chant.  By restoration is meant the modern period beginning with the work of Fr. Lambillotte and Dom Gueranger; therefore historical figures such as Hucbald, Notker, or Guido have not been included.  Out of respect for conventions, there is some deliberate inconsistency in the use of honorifics.  Academic titles are not used for clergy or religious.  Dom is used for solemnly professed monks of the Solesmes, English, and Beuronese congregations and supersedes titles such as Prior or Abbot; Fr. (Father) or Br. (Brother) is used for monks of other Benedictine congregations.  In most of Europe, professors must have completed a habilitation or post-doctoral qualification, which involves work equivalent to a second doctorate.  In the United States, Dr. is generally regarded as higher than Prof. (one of my teachers recalled that in the previous generations, it was not especially uncommon for someone with only a bachelor's degree to hold a full professorship).

For additions or corrections, please contact Patrick Williams: organistAL at aol dot com