He left a strong influence on the new fields of historical criticism and musicology; his work spanned periods of music history from the early Middle Ages to his own time, and embraced research, teaching, writing, and editing of musical editions to a very rigorous degree, including the use of source-critical studies. He was influenced by neo-Kantian philosophy. In his Bach biography, he wrote the first major study of German choral and keyboard music of the 17th century (early baroque).
Books
Most of his papers are divided between the library of the Berlin Hochschule für Musik, the Staatsbibliothek zu Berlin, and the library of the University of ?ódz. He contributed many scholarly articles to periodicals, and wrote articles on Schumann, Spontini, and Weber for Grove's Dictionary of Music and Musicians in 1886.
- Ein Lebensbild Robert Schumanns (Leipzig, 1862)
- Johann Sebastian Bach (Leipzig, 1873—1880, 1962; English translation: 1884—1885, 1899)
- Zur Musik (Berlin, 1892) - 16 essays
- Musikgeschichtliche Aufsätze (Berlin, 1894) - collected essays
Editions
- Dietrich Buxtehude: Orgelwerke (Leipzig, 1876—1877)
- Heinrich Schütz: Sämtliche Werke (Leipzig, 1885—1894)
- Friedrichs des Grossen: Musikalische Werke (Leipzig, 1889)