That's a small enough number that the shipping of the books to the publisher would not be cost-prohibitive, but that enough copies would exist for all the legitimate uses -- solicitation of "blurbs," as well as copies for the author, early reviewers, major bookstore and wholesale buyers, and regional sales reps. For the more elaborately produced volumes, with illustrated wrappers, more thorough promotional material, and often with a more "finished" look to the typesetting and pagination, the lower range of cost- effectiveness would likely be found at around 500 copies, and in many cases could be more. At least one advance reading copy -- Gorky Park, which was the "breakthrough" book for its author, Martin Cruz Smith -- had a print run of 1500 copies, and then went back to press for a second printing of another 1000 copies -- all prior to publication. This is probably more common than we know, but is seldom reported outside of the publishing house in question. In recent years, changes in printing technology have enabled more lavish productions on even small print runs: desktop publishing systems, color scanners and digital technology have meant that more and more proofs can have a polished, finished look to them; this has clouded the distinction somewhat between what should rightly be called "uncorrected proofs" and what would more appropriately be viewed as "advance reading copies.
 Uncorrected proof describes the penultimate proof version (on paper or in digital form) yet to receive final author and publisher approval, the term appearing on the covers of advance reading copies.