This book of images is wonderful -- it's a proper view of the whole
factory, not just its publicity output.  I love an image of a load of
workers around an instrument.  The sheer inventiveness of Hupfeld and
its huge range of massively-engineered products is quite something to
behold.

The one-armed pianist in one photo is the famous Paul Wittgenstein,
who commissioned pieces for the left hand from a number of renowned
composers.  He had 6 rolls issued by Hupfeld.  I have one, which I
recorded -- a bit warped so it plays extra notes from time to time.
But these are the only rolls recorded by a one-armed pianist that
I'm aware of.  https://www.youtube.com/watch?v=rw3r3UY73lk
 

Julian Dyer