Thirteen leaves of the Liber Amicorum contain pieces of music, twelve of which are probably original and were composed specially for the book. Not only can you look at them, you can listen to them as well.
The music is performed by:
Frederike Bruin (alto/mezzo-soprano)
Jean Hellwig (tenor)
Barbara Klein (alto/mezzo-soprano)
Pieter Visser (bass, baritone)
Tomoko Mukaiyama (piano).
Michel Schöpping was responsible for the recording and technique.