Because nobody had undertaken to write it. Fred Schwan and I long said that we would be delighted to buy a book on WWII numismatics if someone would write it (and we continue to say that about the long-delayed second edition). There are only so many people who will take the time to research and write on arcane subjects that may have only a few score potential readers.

"tiny oval library stamp on verso of each plate"

I love it! An owner (or librarian) who wants to curtail the surreptitious razoring of pages for resale. Would that all libraries undertook such precautions. Then all we would need is a book publishing the owner of each such library stamp, so that larcenous sales could be prosecuted.

There is a tiny inscription at the bottom rim of the dragon side that appears to be in Roman letters - what does it say? The "Chinese" is very stylized - I can make out only the character for luck or good fortune on the dragon side, and possibly a name, Kung Kuan, on the bottom of the portrait side.

"The Bureau of Engraving and Printing ... has identified a problem with sporadic creasing of the paper during printing of the new $100 note."

I'm not surprised. The new "Motion" thread embedded in the paper adds localized thickness to the paper - if you look at a stack of the sheets, there is a noticeable hump in it. But considering how long they have been printing these, I'd have thought they would have worked out any problems before now.