An extremely rare map of Middle-earth annotated by “The Lord of the Rings” author JRR Tolkien is on sale in the U.K. for $92,138.

The map is one of a number of works by celebrated illustrator Pauline Baynes being sold by Oxford-based Blackwell’s Rare Books.

Blackwell’s told FoxNews.com that the map was found in a copy of “The Lord of the Rings” that belonged to Baynes. The late illustrator had worked on a color map of Middle-earth for Tolkien that was published in 1970.

“An important document, and perhaps the finest piece of Tolkien ephemera to emerge in the last 20 years at least,” explains Blackwell’s, in its sales brochure. “This constitutes the working material for Pauline Baynes’s colour ‘Map of Middle Earth’, published by Allen & Unwin in 1970.”

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The map, which measures 16.5 inches by 18 inches, features copious annotation by Tolkien in green ink or pencil, with additional annotation by Baynes in blue ink or pencil.

“The majority of the annotation on the map is in Tolkien’s hand and demonstrates the exacting nature of his creative vision: whilst he continues to be attentive to the placenames (ensuring the correct representation of existing ones and providing additional ones), he makes numerous suggestions regarding pictorial aspects - both in the form of positioning, but also the various flora and fauna or vessels through which the various locations are represented,” explains Blackwell’s, in its brochure.

In a fascinating comment at the foot of the map Tolkien states that “Hobbiton is assumed to be approx. at latitude of Oxford.” The author also uses the Italian city of Ravenna, Belgrade, Cyprus, and Jerusalem as other reference points.

A spokeswoman for Blackwell’s told FoxNews.com that the rare books specialist is not exactly sure when the map was found. “In the last couple of years is as accurate as we can be,” she explained, via email.

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