New Yorker Hiroshima Issue
The entire contents of The New Yorker issue containing John Hersey's Hiroshima essay had an unfortunate cover illustration. The cover depicted a leisurely American community swimming, biking, and playing. It had gone to print and was about to be distributed nationwide. The obvious problem: the cover art would not prepare readers for what they were about to encounter inside. It was too late to delay the issue and change the art. It was too late to slow up putting in the mail the copies that would get to anywhere outside NYC, but it was not too late to print a bellyband to wrap around the issue for the issues that could be dropped a day or two later. So that's exactly what they did.
Typically, these bellybands are removed and discarded by readers or librarians, making those still in existence. However, by chance one librarian did maintain a full copy of this New Yorker Hiroshima Issue complete with bellyband and The New Yorker naturally had the scoop.