A phrase that seems to have crept in to bookselling jargon recently is 'primary source edition'. I first noticed it when it was used to describe a book I bought on Ebay this week. I had assumed that it was just the seller's way of saying that it was the first edition or a very early reprint because I recognised the edition from his online image but when he later apologised for mis-describing the book I decided I must try and establish what the expression means.
In brief, it seems to have been adopted by the publishers of 'print-on-demand' books to indicate that they had scanned the original edition of the title. Thus a 'primary source edition' sounds rather better than it really is (and was fortunately not what I had bought on Ebay!). For full details of the brief research and some of the faults likely to be encountered with 'primary source editions' see the account on ABfaR's blog.