I'm sure you're right, Solange.
Escher was a master printmaker. His work is often poo-pooed by the fine art crowd, however. Perhaps unfairly. I admire the technical achievement evident in his work and, of course, his unique perspective.
Tastes wax and wane, but, alas, auction prices are the common measure for modern art. Only the test of time will decide Escher's true stature.
How To Identify Prints
I recommend an hour or two with this reference book and a cheap pocket microscope to anyone interested in buying prints at auctions, estate sales, or wherever. A little background can save or make your day.
http://www.amazon.com/How-Identify-Prints-Second-Edition/dp/0500284806
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