Despite their variable quality of sound (some are quite good while others are nearly inaudible), the cylinders have great historical value thanks to the unique aural picture they document of pre-World War I singers in performance at an opera house with a full orchestra.
Mapleson was apparently enchanted with the acoustic device, and on March 21, 1900, his friend, the cellist and occasional composer Leo Stern, presented him with attachments for it: Bettini recorder and reproducer units.
At that point Mapleson either lost interest or was forbidden by the Met's management from continuing his recording activities (although a few cylinders exist of orchestral rehearsals or concerts dating from 1904).
[citation needed] With the co-operation of collectors, by 1962 eventually all existing Mapleson Cylinders had become the property of The Rodgers and Hammerstein Archives of Recorded Sound, a division of The New York Public Library.
In 1985, under the direction of David Hall, the library transferred all the existing cylinders to six LPs which were released with a 72-page booklet containing translations and extensive historical and biographical notes.
A number of the cylinders have been reissued on CD by the Romophone and Marston record labels as part of wider anthologies devoted to individual singers.