[ Ref. 100308 MMDigest, "US Piano Roll Designations" ]

Regarding US Music "Library Edition rolls, "Library Edition" was
a series issued by US Music, apparently mainly around the mid 1920s,
say late 1923 to late 1925.

The "Library Edition" rolls were the "chestnuts" or "war horses"
of their catalog, the ones that one would assume should be in the
permanent roll library of any discerning music fan.  Other than
the distinctive labeling and lack of words, there was nothing to
differentiate the rolls themselves.   Aeolian had a similar series,
called "Pianolist's Library" rolls, which were identical to their
Themodist-Metrostyle Rolls, and were the 'standard repertoire' pieces.

The series was edited by McNair Ilgenfritz, a composer/arranger who
worked for US Music and, I think, several other firms at one time or
another.  Ilgenfritz was an interesting fellow in his own right.

Ref.
http://www.arcade-museum.com/mtr/MTR-1924-79-13/MTR-1924-79-13-01.pdf 
http://www.arcade-museum.com/presto/PRESTO-1925-2026/PRESTO-1925-2026-21.pdf 

Bryan Cather