After leaving a slightly negative review I noticed this page folded into the packing sheet, lovingly titled:
Yes! The publisher intentionally reduces the value of their own books so that bookstores dumb enough to accept returns without receipts don't get scammed! Furthermore, Amazon has changed their policy so that bookstores aren't allowed to tell people about this stupid practice until the book actually arrives! That makes perfect sense! I'm inclined to think that somebody is being dishonest here.
About the black marking............
You may find a black permanent marker line on the bottom or top of your book, commonly referred to as a "Remainder Mark."
This is not somebody being careless.
And it does not mean that your book is not new - it is brand new.
This is placed on the book by the publisher. The publisher puts this here to ensure that the book, once sold to you, at a significant price discount, is not then taken back to a store for credit or exchange. The mark protects the publisher and the retailer, so it is very important.
Books with these marks are generally either overstocked books, or books that have been returned to the publisher, or distributor, by a store for credit.
You will find that nearly all new books sold on Amazon by marketplace sellers have a black line, or a remainder mark. (sometimes, it can be a red or a black dot, a yellow line, you get the point.........).
We used to state this clearly in the listing description, but Amazon recently changed their listing policy.
The practice is bull, of course. I ordered another book from the same author, and it arrived in a protective plastic case, in pristine condition and with no ugly marker swipe across the spine.