Many of Yale's musical treasures have been digitized, and are available on the Web. Some highlights:
- Johann Sebastian Bach's Clavier-Büchlein vor Wilhelm Friedemann Bach, a book-length manuscript Bach wrote to help teach his ten-year-old son.
- Johannes Brahms's Capriccio, Op. 76, no. 1, a gift from the composer to his friend Clara Schumann.
- Robert Schumann's sketches for his Etudes symphoniques.
- Felix Mendelssohn's Lied ohne Worte, Op. 19, no. 2.
- The Wickhambrook Manuscript, a collection of English lute music compiled in the 1590s, by various composers including John Dowland. (The digitized version of this manuscript is available only to computers on the Yale network.)
- The Lowell Mason Codex, a collection of 17th and 18th century organ music by various composers including Buxtehude.
- The Mellon Chansonnier, a beautiful manuscript from 15th-century Naples that belongs to the Beinecke Rare Book and Manuscript Library.
- The Miscellaneous Letters and Documents File, Misc. Ms. 372, a collection of more than 900 letters by notable musicians. 59 of the letters are available online.
- Music theory treatises: a collection of 19th-century books that were digitized for Prof. Patrick McCreless's course on the theory and aesthetics of music in the 19th century.
- Manuscripts, Rare Editions, Trading Cards, and Portraits: a miscellany of materials, ranging from Gilbert and Sullivan trading cards through historical American sheet music to caricatures of great composers.
- Copyist's manuscript of selections from J.S. Bach's Orgelbüchlein (Johann Christian Kleingünther, 1747).
- Manuscripts and Rare Books at the Gilmore Music Library (open access): miscellaneous digitized items, including Henech Kon's Yiddish opera Bas-Sheva (manuscript) and early printed editions of works by Bach, Mozart, Clementi, and other composers.
A few places to look for more digitized treasures: