The following are brief sound clips from some of the music referenced in the novel.
I have included detailed information about the recordings and artists.

Aria from Johann Sebastian Bach's
The Goldberg Variations, BWV 988
Performed by Glenn Gould (CBS Records, 1982)

Chapter 1 "Night Terrors"
Johann Sebastian Bach (1685-1750)
Cantata BWV 82 ("Ich habe genug")
Performed by the Academy of St. Martin-in-the-Fields
Sir Neville Marriner, conductor, John Shirley-Quirk, bass
(London Records, 1991)

Chapter 9 "Memento Mori"
William Byrd (1543-1623)
Ave Verum Corpus
Performed by The Tallis Scholars, Peter Phillips, director
(Gimmell Records, 1991)

"Parasomnia" [between Chapter 9 and 10]
Giovanni Battista Pergolesi (1710-1736)
Stabat Mater
Performed by The King's Consort, Robet King, conductor,
Gillian Fisher, soprano, Michael Chance, countertenor
(Hyperion Records, 1987)

Chapter 15 "Dead Ends"
Igor Stravinsky (1822-1971)
Symphony of Psalms
Performed by English Bach Festival Chorus
and the London Symphony Orchestra,
Leonard Bernstein, conductor
(Sony Classical, 1993)

Chapter 18 "Transmutations"
Johann Sebastian Bach (1685-1750)
Cantata BWV 131 ("Aus der Tiefe rufe ich, Herr, zu dir")
Performed by Bach Collegium Japan, Masaaki Suzuki, director,
Yoshikazu Mera, countertenor (BIS Records, 1995)

"Parasomnia" [between Chapter 18 and 19]
Duke Ellington
"East St. Louis Toodle-oo"
Performed by Duke Ellington and His Orchestra
Recorded on March 5, 1937

Chapter 26 "Mrs. Brinkmeyer"
Johann Sebastian Bach (1685-1750)
Allemande from Partita No. 2 in C minor, BWV 826
Performed by Martha Argerich (EMI Classics, 2000)

John Coltrane
"Someday My Prince Will Come"
(CBS Records, 1990)

"Parasomnia" [between Chapter 30 and 31]
Wolfgang Amadeus Mozart (1756-1791)
Clarinet Concerto in A major, K. 622
Performed by Academy of Ancient Music
Christopher Hogwood, conductor
Anthony Pay, basset clarinet