I was just checking the delivery status of a book I sent  and there is a notation that it is "undeliverable as addressed." 

I do PBS postage and DC, so I used the label as printed by PBS. (I already got my credit, so I'm not concerned about that)...but what happens now? Will it come back to me?  Will I have to re-send it? 

Oh, and get this, my first lost book happened today.  Are these going to reflect badly on my account?  I did everything by the book!!!

Help!

I would PM the person you sent it to and ask if there's a problem with their address in the PBS system.  If the address is correct you can take the package back to the PO and ask them why it came back to you. It could just be that it was delivered to the wrong house and got incorrectly marked as having a wrong address.  It should come back to you. Hopefully they won't charge postage to send it back.  If the requestor entered their address wrong into PBS-I'm not sure if you have to send the book out again or not.  You shouldn't have to pay postage twice for their mistake. But it could just be a PO error.  It's hard to say until the package comes back. 

Thank you.  Now what do I do if the person won't respond to my pm's?  I know I'm impatient by nature....so I was thinking I'd wait a week?

wait a week since not everyone is on here all the time (but I wish there were!) but unless the book comes back to you I wouldn't worry about it too much because you can't do anything if you don't have the book!

and one lost book isn't going to hurt you at all, it is multiple books that could be a problem

Thank you.  I feel much better! ;-)