Jody recommended Art Reblitz's book on piano servicing as a good book
for newcomers.  If the newcomer is interested in doing hands-on work
Art's book is a must, but another must is Art's companion book on
player mechanisms.  Highly recommended also is Craig Brougher's book.

However, I would recommend starting by reading the historical books --
probably in the chronological order in which they were published:

  Harvey Roehl's "Put Another Nickel In"

  Q. David Bower's "Encyclopedia of Automatic Musical Instruments"
  (the Bible of the business, called the "Encyclopedia" for short)

  Reblitz-Bowers "Treasures of Mechanical Music"

These for starters, at least.  Eric Cockayne's book on Fairground
organs is another early historical book covering the field from a
European perspective.

If you are into music boxes, there is a whole different reading list,
such as the Ord-Hume book.  But that is for someone else to supply.

Matthew Caulfield