The Sword in the Stone is a novel by T. H. White, published in 1938, initially a stand-alone work but now the first part of a The Once and Future King.

Walt Disney Productions adapted the story to an animated film, and the BBC adapted it to radio.

"Who so Pulleth Out This Sword of this Stone and Anvil, is Rightwise King Born of All England."

The novel is about a young boy named Wart who befriends a magician named Merlyn. As we suspect all along, but only find out for sure at the end, Wart is actually the future King Arthur. The title refers to a sword that was magically embedded in a stone so that only the future, true-born king of England would be able to remove it.

The premise is that King Arthur's youth, not dealt with in Thomas Malory, was a time when he was tutored by Merlyn to prepare him for the use of power and royal life. Merlyn magically turns Wart into various animals at times. He also has more normal adventures, at one point meeting the outlaw Robin Wood.

The setting is loosely based on medieval England, and in places it incorporates White's considerable knowledge of medieval culture (as in relation to hunting, falconry and jousting).

However it makes no attempt at consistent historical accuracy, and incorporates some obvious anachronisms (aided by the concept that Merlyn lives backwards in time rather than forwards, unlike everyone else).
 

The version appearing in 1959 in the tetralogy was substantially revised, partly to incorporate events and themes that White had originally intended to cover in a fifth volume (which was finally published after his death, as The Book of Merlyn).

To this end, the revised version includes several new episodes, including e.g. a pacifist passage in which King Arthur is transformed into a bird that flies so high as to not be able to perceive national boundaries.

It leaves out some of the episodes that had appeared in the original (notably  Merlyn's battle with Madam Mim which appeared in the Walt Disney film).

However, many critics considered that the revised version was actually inferior to the original. Some publishers carried on using the original version, at least when the book was published independently of the tetralogy.

The reasons White made these revisions are open to speculation. The Sword in the Stone, although it includes some serious themes, is to some extent a rather whimsical fantasy of Merry England.

Its connection with the classical Arthurian legend was actually rather limited, although what it did take from the Arthurian legend was accurate.