I got a book yesterday.  It was in a 6x9 envelope with the mailing label taped to the front.  No problem.  I got to looking and the thing had no stamps.   Is it possible that it got thru the postal service without a stamp?  It just got me curious about what could have happened.

they might have fallen off and no one caught it later on, that is about the only thing I can think of.

Are you sure they didn't use the pre-printed postage? That would be right on the label.