I requested a book quite some time ago and it has yet to arrive.  The system cancelled the order.  This happened to me once before and eventually the book showed up.  This time is hasn't.  It is still on hold on my wishlist --- at what point should I take it off hold??  Suggestions appreciated.

Just read in another post that one should wait two weeks before obtaining a second book.

I believe the help topics recommend waiting two weeks.

If you are sure the system cancelled the order, that means that either the sender did not respond to the book request, OR the sender accepted it but never marked the book mailed.

In both cases, you are fine to re-order the book whenever you want. (or take it off hold so that the next copy can be posted to you).

If you mean that the book was mailed but you haven't received it yet and now the order is gone, that means that the book went "lost in the mail". There could be a few reasons for this ... the sender mailed it but the PO is really slow, the sender mailed it late, the sender marked it mailed but never really mailed it, etc.

In this case, you should PM the sender and gently ask them if they recall anything happening that would make the book arrive late. If they don't answer you within a few days, I would go ahead and just order another copy of the book. PBS recommends that you wait about 2 weeks after books go lost in themail to re-order, just in case the sender mailed on time but the mail is really slow.

Yes Becky, the help documents recommend waiting two weeks to re-order the book. 

When the book arrives, check the wrapper carefully to see if it's from the first transaction or the second.  If the 'lost' copy shows up, check the mailing info carefully for dates indicating when the book was actually mailed. 

Have you sent a PM to the sender to see if they did in fact mail it and when? I'd send them a PM that you would like to reactivate your wish for the book if they hadn't sent it and if they did, could they please confirm when.

Thank you all so much.  Sara, I used an incorrect terminology --- the book was mailed, just never arrived.  I have been in contact with the sender and she did not use a delivery confirmation but says that she did mail the book.  I will give it a bit more time until I remove the hold on my wishlist.