The sender mixed up the 2 books she was mailing and I received a trade-size paperback, a wishlisted book, but not one on my wishlist.  I PM'd her when I received the wrong book and she said she already knew about it.  The other requestor who received the book that was intended for me said she would just keep the older, mass market paperback that she received in error. 

Guidelines tell how to handle the incorrect-book swap in different scenarios but not how to handle this particular situation.

I do not want the book I received.  The sender told me to keep the book and she would chaulk it up as her loss.  She suggested I do NOT mark the book received and I wouldn't have to pay a credit but neither would she receive a credit.  She suggested I then post this wishlisted book (153 wishers) and thus would get a credit when I mailed it. 

It doesn't seem ethical to let the book that I requested be declared "lost in the mail."  And there are multiple copies of the book I want in the system so I'll have no problem getting a copy.

What actually needs to be done in this situation?

You don't mark a book received until you have the book you ordered.  Since that's not going to happen, since the other member isn't going to "swap" the wrong books back with you, just let it time out of the system.  The error was the sender's, so you can keep and repost the book.

There are more details on what to do, from the sender's perspective, in the Help Center.  Search for "wrong book" (without the " marks) and look at the document called "I sent the wrong book to another member (including: I mixed up two book requests)"  It would be helpful if the sender would contact PBS and ask them to cancel the transaction -- then you could get back on the Wish list that much faster, and be in line for another copy of the book.

Only the sender asking PBS or the 26 day lost deadline will cancel the order. At that point, you will get your credit back.

The sender is essentially correct. 

1. You did not receive the book (or a version of that title) you requested, so do not mark it received...not even RWAP.

2.  The system will mark the book Lost after the specified time has passed.  The other option is for the sender to contact PBS Admin and let them know there has been an error and the receivers will not be exchanging books.  She can request PBS cancel the transaction (sender only, receiving members cannot make this request).  But either way, you will receive a credit refund and be placed back on the wishlist in your previous position.

3. If you wish, you are free to repost the book you received.

It used to be that PBS asked us to not mark a wrong book received at all.  But they added a new option, Wrong Book, Different Title.  This does NOT mark the book received.

• Wrong Book - Different Title
  • this means that the book is totally wrong (wrong title/author) - usually caused by the sender putting the wrong book into the wrapper, or mixing up two book shipments.  See I received a book I didn't request! for more information about this problem.

Which leads to this result:

• Wrong Book - Different Title
  • Again, this means that the book is totally wrong (wrong title/author) - usually caused by the sender putting the wrong book into the wrapper, or mixing up two book shipments
  • You will have a text box - the text you type in will be included in an email, and sent as a Personal Message, to the sender.
  • Choosing this problem type option will NOT mark the book received - you will see the instruction "Note: This book will NOT be marked as received. Please wait until you receive the book that you ordered, then mark it received."
    • The book IS NOT marked received for this problem type because if a sender mixes up two requests or puts the wrong book into a wrapper, usually the sender had the book in question and it can be retrieved and sent to you.
  • If you don't get this book by the system action date, the book will be declared "lost in the mail" - if you get it after that, you need to mark it received from your Transaction Archive, as described in I received a book that was 'lost in the mail'.
  • If the sender cannot send you the correct book, he or she can contact us to cancel this transaction, so that you can try to get the book from another member without having to wait for the system to declare it "Lost in the mail." 
  • See I received a book I didn't request! for more information about the resolution of this problem.

Yay!!  Thanks to our great PBS tean, I can post again without having to go find another computer.  (I'm using IE-10 and none of the previous F12, etc., remedies worked for my computer.)

Just as follow up, I took Emily's advice and followed that particular set of instructions and the problem was easily resolved.

Thanks, all, for the input.

Jan