The Once and Future King
By T.H. White
This is a well-loved retelling of the Arthurian legend, from Arthur's birth to the end of his reign, and is based largely on Sir Thomas Malory's Le Morte Darthur. The musical Camelot was based on it, as was Disney's The Sword in the Stone. After White's death, a conclusion to The Once and Future King was found among his papers; it was published in 1977 as The Book of Merlyn.