I recieved a book today with NO postage on it, no stamp, no postmark, no dc, nothing.

It got here. And it got here fairly quick.  I assume it was just a forgetful poster/sender and an oversight by the PO...

My question is, just out of curiosity, IF the PO would have noticed there was no postage, would it have came to me postage due, or been returned to the sender? 

And more importantly, would you (politely) let the sender know they forgot postage and maybe should double check next time? I'm glad it worked out for me, but I can only imagine someone being very angry if they got a book that had no attempt @ postage and a postage due notice upon recieving the book.

I received one with no postage as well. I think it would depend when they caught it...if at the sending end, it might have gone back to the sender. If it's at your PO, they often give you the opportunity to pay. In my case, I almost always say thanks when I fill out the survey, and I mentioned it arrived quickly  particularly since it had no postage. I didn't suggest the sender do anything (obviously it was an oversight), which she acknowledged in her reply.

I am sort of amazed though, this book came 1/2 way across the country with no postage in 4 days. I've had them come from less distance away with postage and not get here for 3+ weeks! lol

Like I said, glad it worked out and my book didn't get lost in the postal abyss, I just didn't know if PBS ettiquite was to let them know there they forgot postage.

It probably would have arrived postage due, or at least that is what happened to me when the postage fell off one of the books coming to me.

I had a book come with no postage once, but turns out the owner had her DH drop it in my box on the way to work...

The comment about falling off taped surfaces is correct.  I've seen this happen, too, and you really should apply the stamps to bare paper, if at all possible.  The senders who "mummify" their books will have trouble with this, of course.  (Why anybody would go to that effort which is NOT NECESSARY OR DESIRABLE is a mystery to me. )

I have usually cut out the label with the addresses on it and glued it to the package, but if the backing is slippery at all, or on large packages, I put a piece of transparent tape pver the label, leaving space for the stamps on the baare paper, but making sure that the label doesn't go to PO twilight zone.  I've done this since the PO returned a label with all of the stamps on it to me after it had fallen off the package of 4 books (they were wrapped in a somewhat slippery plastic wrap)    Have had no additional prolems of this nature since.

The postal rule is if it has NO postage on it, it is supposed to be returned to the sender.

If it has any postage on it, it is supposed to be sent on, postage due.

In actual fact, though, if something got as far as my office with no postage, I would offer the addressee the opportunity to pay the postage rather than send it (potentially) clear back across the country again.

Occassionally USPS doesn't catch missing postage, and once in a while the postage falls off in transit.

The ladies at my Post Office affix the postage with a very light touch ... so light I can often see that the stamp is not even attached completely. It is just barely attached.

Yes, I am that rude customer who reaches across the counter to press the postage on more firmly once they move on to the next package. I can't stop myself from doing it.