Hi.
This is a followup to my response about writing PDF tools in C.

The PDF book I referred to is 'Portable Document Format Reference Manual'
(I think... the book is not here today).

Adobe has a PDF title of the same name at their site (1.5MB), so
you may be able to get it on-line at:
http://www.adobe.com/supportservice/devrelations/devtechnotes.html
(Look for the 'Portable Document Format Reference Manual' file).

To understand the actual PDF commands (as compared to the document
structure itself), you need to know a fair amount of PostScript.

There are PostScript books out there; I have 'Teach Yourself Postscript'
and Adobe's Postscript Reference ("the red book").

Mark