Explanation: First of all, Graphic Arts Monthly was a respected trade publication covering (obviously) the graphic arts, printing, advertising and publishing industries.
Second, about the phrase etaoin shrdlu, here’s a good quote from Wikipedia:
“The letters on type-casting machine keyboards (such as Linotype and Intertype) were arranged by letter frequency, so e-t-a-o-i-n s-h-r-d-l-u were the lowercase keys in the first two vertical columns on the left side of the keyboard. When operators made a mistake in composing, they would often finish the line by running a finger down the first two columns of the keyboard and then start over. Occasionally the faulty line of hot-metal type would be overlooked and printed erroneously.
A documentary about the last issue of The New York Times to be composed in the hot-metal printing process (2 July 1978) was titled Farewell, Etaoin Shrdlu.“
So what it all adds up to is that in the good old days when printing type was cast from hot metal, there was a slight chance that you could come across the phrase etaoin shrdlu in your newspaper article, by accident. Sometimes I think the phrase was inserted on purpose, by typesetters who fancied themselves practical jokers.
The sad fact is that the entire hot metal typesetting industry was decimated and destroyed when computer technology took over and print and advertising type could be digitally created by anybody with a keyboard and the right software.
And now you also know why tnshrdl are the first consonants selected on “Wheel of Fortune”, and why the vowels eaoiu are bought in that order.