I have 2 WL books en route to me. One was sent the 5th, the other the 6th. Both used PBS postage so the senders have the credits. The tracking on PBS merely shows that electronic shipping notices were received by the PO and using the ISBNs on USPS shows nothing further. Today PBS sent me the 'have you received this book' email for the one sent the 5th.

Are both these books stuck in USPS limbo? And is there any way to help move them along to me?

I also have  one that was mailed on 1/8 and sat at the post office until 1/15, now it says that it is en route to me. The 'have you received this boo' alert is an automatic email. The system won't do anything until they go lost.

Is there any point to taking the tracking numbers to my PO and asking them to put both packages on a watch list?

Some books never get scanned until they're delivered and some not even then. I use a tracking number on every book and enter it into my informed delivery even without printable postage and a few times the book was marked received but the package was never tracked once it left my local post office. It's only been two weeks for those books, you could ask them to run a search if you have to stop by the PO anyway, but as you know sometimes MM packages just take longer. I've found the automated alerts are fairly up to date and accurate (if it actually gets scanned through the system enroute) and I believe if you ask at the desk they would be looking at the same system that generates the alerts.

One of the books is finally moving according to USPS tracking. Today it's marked as accepted by USPS and departing the original post office. The other is still marked only  as having the shipping label created.

I ordered some books off a website that I was certain had gone lost--the boxes arrived in Las Vegas on 1/3 and then nothing for 13 days. Suddenly they were all on the move again and all have been delivered in the last couple of days. There is still hope!

Honestly, I think that it is more likely that the sender is at fault.  In late Nov a WL book was posted to me and I accepted immediately.  Sender then printed postage and marked the book mailed within the PBS system.  Then nothing.  PO tracking said label created and electronic info rec'd by the PO but there was never an acceptance scan and nothing else happened for weeks.  I kept getting the automated emails too asking if I had rec'd the book.  Finally, just before the book was going to time out, suddenly there was an acceptance scan at the PO and then the book moved through the PO system and got to me very quickly.  I am convinced that the sender did not even mail the book until the date of the acceptance scan.  I know the PO is not infallable, but I think it is more likely that the sender just did not mail the book until weeks later.  If a book fails to move once there's an acceptance scan, it is defintely a PO problem, but with no acceptance scan, I tend to think it is a sender problem.

How does that work with USPS? I thought you had to mail the book within 48hrs of printing PBS postage or the PO wouldn't accept the postage. Is that wrong?

I know the tracking information first states 'electronic shipping info received' with the codicil that it doesn't mean USPS actually has possession of the package.

Tracking for one of the ones mentioned in my OP---the one that seems to have actually started moving through the postal system---shows as 'label created', then a week later 'electronic shipping info received', followed by 'acceptence' 5 days later still. And apparently the postage is still good?

As you know the post office has the right to open and inspect media mail. Perhaps someone does this to some book packages, thinks it is an interesting title, then takes it home to read and will re-insert it into the package when they finish it.

Now the 2nd package I mentioned in the OP is on the move. Who knows what happens. I doubt postmarks will give any clue.

As far as opening for inspection, doesn't USPS mark packages that have been opened? Maybe not. In the end it's that I'm short on patience.

"Electronic Shipping Info Received" has to do with whatever day the sender picked for the postage mailing date. If I printed out postage today I could select the date I was going to ship it on. It is possible I drop it in the blue box earlier than that day selected though. But nothing will show on details until a day after that date.

Sometimes books I mail get "acceptance" scans sometimes not and there won't be any till "enroute" and every once in a while no scans to delivery.

I have one mailed on 6 JAN that has been stuck in Seattle since the 8th apparently. 

Marya - yes, I think that the postage is only supposed to be good for a certain amount of time but I also think that the PO can't possibly catch every single instance when something isn't mailed within that time frame, especially if the sender mails from a postal drop box or a postal contractor like at a grocery store.  I imagine some do get refused acceptance at the counter or returned to sender for "stale" postage, but I also think that a fair number of packages get sent on their way too.

I still haven't received either book but hope they are both still moving through the postal system. As luck would have it, one is the newest book in my favorite series.

The book stuck in Seattle is finally in Florida.....will see how long it takes to travel what is a 4 hour drive from Jacksonville.

USPS is full of surprises. I'm waiting on book parcels maile in this country on 5 Jan and 6 Jan. Neither has arrived. On 13 Jan I mailed a friend on rural England a package and, bingo!, it's already delivered. So 19 and 18 days travel time in country nets no packages, whilst 11 days abroad and the parcel's on the recipient's doorstep before she has time to finish her tea. 

Both books finally arrived today along with another mailed on the 18th from just as far away as the slow travelers.

Glad your books arrived!! I just got a priority mail package this week mailed on January 5th.

Thanks. PBS postage seems to slow books down. The ones without get to me more quuickly.

On TH we finally received a 5x7 manilla envelope my MIL mailed on 10 JAN containing cards and giftcards.  She was really worried they had gone lost in mail but I told her to hang on and give it a few more days. 

I know it's a bit late to put my two cents in but ...

A lot depends on the route a book takes. The USPS Seattle Network Distribution Center is a black hole that shows up as FEDERAL WAY in tracking that will hold the book for a week or better. The Tennessee distribution center will hold a book for the better part of a week or more. But then I had a book coming from NJ that only took a couple of days (I'm in Houston).

There are also times the PO just doesn't scan the book. Maybe they get busy or something. Who knows? I had one that didn't show up for a week until it hit the Houston regional center and then I got it the next day (the local mail is really fast here).

And there may be a problem with the sender. I had some books to mail and one fell under the car seat. I found it a couple of weeks later when I cleaned out the car and sent it on. Not anything I did on purpose, but things happen. Now I double-check everything.

Sometimes I think the sender uses PBS tracking, gets the credit, and then for whatever reason doesn't send the book right away. 

Or maybe they gave it to the SO to drop in the mail and he forgot and it slid under the front seat.

Not that that has ever happened to me . . .