unlisted Spanish era stamps

Surprising is the number of stamps listed by Don Peterson in Unlisted Scott Catalogue Surcharged Stamps of the 1881-1888 Spanish Philippine Period.

This was published in 1997 by the International Philippine Philatelic Society.

My copy is signed "17 of 200" by the author.

The color plates are indeed helpful, as the author says in the Introduction.

The list of known forgeries is helpful, too.