The Witch in the Wood is somewhat different from The Queen of Air and Darkness, which has been published in The Once and Future King (1958).
The Queen of Air and Darkness, is the second book in his epic work, The Once and Future King. It continues the story of the newly-crowned King Arthur, his tutelage by the wise Merlyn, his war against King Lot, and also introduces the Orkney clan, a group of characters who would cause the eventual downfall of the king.
The original second book in the series was The Witch in the Wood, published in 1939. It has the same general outline as the replacement work, but is substantially longer and most of the text is different.