I want to find out more about who the author of this book was, what the
book is about and its place in litarary history. Any recent
information on it value will bring an additional $15.00 bonus.
The book is by Gabrielis Pereira de Castro. The Title is "Tractatus de
man v regia". The year it was published was 1673. It appears to be in
Latin. It has its original velume cover and is in outstanding condition.

Hello.

The author, Gabriel Pereira de Castro (1571-1632), was born in Braga,
Portugal. He was an ordained priest.  He was also a professor, judge,
and poet.  Additionally, he was the Solicitor General of Portugal's
military.  He wrote treatises on law. He also wrote poetry in
Portuguese, Spanish and Latin.
source:
Project Vercial: Gabriel Pereira de Castro 
http://www.ipn.pt/literatura/gcastro.htm


Your book, "Tractatus De Manu Regia," ("Tract from the Royal Hand") is
one of Gabriel Pereira de Castro's legal treatises. The book is about
the public and religious laws of Portugal.

See the catalog entry at Tulane Law Library:

Author: Pereira de Castro, Gabriel, 1571-1632
Title: Tractatus de manu regia
Imprint: Lugduni : sumptibus Claudii Bourgeat, 1673
...
Subject: Public law -- Portugal
         Constitutional law -- Portugal
http://library.law.tulane.edu/search/t?SEARCH=tractatus+de+manu

There are also copies of the book at the University of California at
Berkeley. Berkeley's catalog entry also lists the following subjects
covered in "Tractatus de manu regia":

Subject:   Church and state -- Portugal.
 Prerogative, Royal -- Portugal.
 Ecclesiastical law -- Portugal.
 Popes -- Temporal power.

Unfortunately, the catalog there does not permit direct linking.
However, you may view the catalog entry by going to the following page
and doing a TITLE search for "Tractatus de manu regia":
http://melvyl.cdlib.org/F/?func=file&file_name=find-b&local_base=cdl90
 
--------

As for your question about the value...  The book is quite rare. There
are only a half-dozen or so library copies in the United States.

Currently, there's one copy for sale from a dealer in Switzerland. 
He's asking $697.92.  See his listing on Abebooks.com:
http://dogbert.abebooks.com/servlet/BookDetailsPL?bi=162261154

---------
search strategy:
"tractatus de * regia"
"de manu regia" PEREIRA CASTRO
PEREIRA CASTRO, Gabriel de
abebooks.com

I hope this helps.

Fantastic work. Thanks. I am including your bonus.

Thank you for the tip.
-juggler