I requested a WL book on Sept. 26th and it was marked mailed on Sept. 30th.

The swapper used DC. I've been checking the map and the truck has been ontop of me for the last couple days, but I also have been checking DC scans and all it shows is: 9/30/2013 10:45 AM - Electronic Shipping Info Received - MARYSVILLE,WA

Would this be considered a lost book already or should I just wait it out?

Definitely wait and see. The truck is mostly for entertainment purposes, so I wouldn't pay too much attention to it (i.e. it's a guestimate based, I believe, on averages). The book could be sitting somewhere, unscanned - or the person could have mailed it late. Really, it could be anything. It's still under two weeks. All kinds of things can happen in transit.

Would this be considered a lost book already or should I just wait it out?

If you check the order on your home page, each book shipped to you will have an estimated date that it should be delivered by. There's also a "Date of System Action". That's the date PBS will consider it lost if you don't mark it received. They ask you not to contact them about the book before then.

I'd also wait before contacting the sender until it's just about to go lost. Unless they didn't mail it on time, there's really nothing they can do about it once the P.O. has it. About all you can do is confirm with them that it was mailed on the date they said they mailed it, or if it actually went out a few days later then you can give it another few days. 

PBS suggests waiting a couple more weeks in the case of a lost book in case it shows up. Media mail rate is very low priority, so flooding and other national disasters can prolong it even more. Books coming in from outside the continental US can take longer because they have to be shipped to the mainland.

And as Caviglia says, the truck is for entertainment only. The site can only tell where your book is when it gets scanned, and many books don't seem to ever get scanned at all. So the truck can't be used to really tell what's happening.

I agree with Caviglia.  It would be unusual for someone to spring for PBS DC or PBS postage and then not mail the book at all, although it's possible.  (Maybe she marked it mailed, but the book slid under the seat and didn't get mailed with the other packages.  Or something.)  I'd wait a week, and then would send a PM saying something like, "I just wanted to let you know the book hasn't arrived yet.  I've been watching for it.  I realize that the server will be marking it "lost" soon, and I notice that the Post Office hasn't scanned the package yet.  Please let me know if it's been returned to you, or if there are any other issues you know of with the package."

ETA: Posting at the same time as Cindy :-)
 

Also not all of the Postal Centers are real active in doing the scan that they're supposed to be doing, so if it didn't get scanned, it could be traveling on it's merry way just fine, you just don't know that it is.  Good luck. Pat

Depends on if the sender used PBS postage/DC or just DC.  The PBS postage doesn't always show the enroute scans, can't remember why (kinda winging it from memory here)...but IIRC there's a place here at PBS that it can be checked??  This was an issue for gamers when the scans quit showing up under details for that series of DC numbers. 

DC only, with stamps or counter postage should pick up an acceptance scan or enroute scans (different number series on the DC).  IIRC the enroute scans are mostly automated these days, and do not depend on employees with hand scanners.  Although a few of my DC only books do slip through with only a delivery scan these days, most will have an acceptance scan from the PO and about 90% will pick up an enroute sort scan from my MM sorting center (Federal Way, probably the same as Marysville).

If the sender used DC (without PBS postage) and there's no scans on the details page...there's an increased chance the book didn't get mailed or has gone astray.  I'm less familiar with the printable postage option.

There is a special PBS page to track the 9452 numbers.  PBS track

For some reason they can't be tracked on the USPS website.  

Many local branches have stopped scanning the tracking until it reaches the sorting hub and the delivery branch.  I think it is a local decision.  Sort of a balance between cost and how close your branch is to being closed down unless you can prove traffic?

Thanks for all the replies you guys! 

As you suggested Emily, I did try the PBS Tracking link & my results were:

Tracking Number: 9452110200817013999407 
Status: Found - No Status
Message: Found - No Status

I guess I'll just wait and see what happens!

BTW - "Electronic Shipping Info Received" merely means that an electronic barcode was generated.  In itself, this notation is no indication whether or not the package is in the hands of the USPS.

I've had three books mailed at the same time before, where two where the scans appeared almost immediately. The third for someone reason had the scans delayed in showing until it was delivered then they all showed up at once.

If the printer ink was faint on the barcodes those usually don't get picked up by the scanner. I think tape over the barcode can cause problems too.

Hopefully the book gets to you soon.