Most of the book takes place in Gramarye, the name that White gives to Britain, and chronicles the youth and education of King Arthur, his rule as a king, and the romance between Sir Lancelot and Queen Guinevere. Arthur is supposed to have lived in the 5th and 6th centuries, but the book is set around the 14th century. Arthur is portrayed as an Anglo-Norman rather than a Briton; White refers to the actual monarchs of that period as "mythical". The book ends immediately before Arthur's final battle against his illegitimate son Mordred. White acknowledged that his book's source material is loosely derived from Le Morte d'Arthur, although he reinterprets the events of that story from the perspective of a world recovering from World War II.
The book is divided into four parts:
- The Sword in the Stone (1938), detailing the youth of Arthur (a revised text of the original publication, which both adds and removes certain parts)
- The Queen of Air and Darkness (1939), published separately in somewhat different form as The Witch in the Wood
- The Ill-Made Knight (1940), dealing mainly with the character of Lancelot
- The Candle in the Wind (1958), first published in the composite edition
A final part called The Book of Merlyn (written 1941, published 1977) was published separately following White's death. It chronicles Arthur's final lessons from Merlyn before his death, although some parts of it were incorporated into the final editions of the previous books, mostly The Sword in the Stone, after White became aware that the compiled text of The Once and Future King would not include his final volume. The Book of Merlyn was the volume that first contained the adventures with the ants and the geese. However, it still has independent value as the only text in which all Arthur's animals are brought together, and the final parts of his life are related.[3]
