A copy of Sir Thomas Malory's Le Mort d'Arthur is among the highlights of a sale at PBA Galleries in San Francisco on September 25, with a valuation of $30,000-40,000.
Published by William Stansby in London in 1634, the book is among the earliest available versions of the collection - which compiles the legends of King Arthur.
The edition was published by 17th century printer William Stansby
Only 14 earlier copies are known, the majority of which are not in circulation.
The author's identity has been a source of contention over the years, but he is commonly acknowledged to have been Sir Thomas Malory of Newbold Revel in Warwickshire.
It's thought he began writing the book while serving time for a string of offences (including extortion, kidnapping and robbery) during the 1450s and finished it in around 1470.
Arthurian legends had been circulating in Britain since the 5th and 6th centuries.
Arthur is alleged to have led the Britons against the onslaught of the Saxons, although the accounts of his life are so tied up in myth that it remains unclear as to whether he ever existed.
He is first mentioned in the Historia Brittonum, a ninth century history of the British Isles.
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