I quote from the scanned manual (page 1): "There is a short excursion into the history of the colonial age on the CD as a pdf file." Unfortunately, this file isn't included in the downloadable additional content of the GOG release. Would it be possible to add it? Thank you.

You might possibly want to contact gog support directly via email about that, they do read the forums but it may take them a while to find this post.

Like Ralackk suggested, you should contact GOG support about this.
I'll add that, though, that *if* it is available and can be found somewhere (p.e. Kalypso has a copy /mind you, they aren't the original publisher!/), then there is a good chance GOG will put it up for download.

Anyone figure this out yet?