rare book- "aggregates type 356 b, accessories type 356 b, conversion and dispatch sets"

Yes, that is a mouthfull!  PORSCHE in the early days had part numbers that started with the letter P.  Later, they changed to a more manageable and meaningful part number that was longer.  In order to make the transition, the early part numbers had to be obsoleted and changed to the new numbers.  This book was issued to make that happen.  
There are a lot of original parts books out there, many of the owners of the 356's have an original or copy of the parts books and workshop manuals.  They are fairly common.  This particular book, which was issued to the dealers, is far more rare today.  Actually, I only know of one other copy, but I am sure there are others.
Below are some photos of some pages and of the book.  It is on the second shelf with the crest on the cover.