Beagle has said that his primary interest is the "common ground that the Perfectly Serious shares with the Absurd, the matter-of-fact with the terrifying, the costume with the skin, the mask with the face." The dominant narrative technique of The Folk of the Air is the shifting from realism to fantasy without letting the reader know precisely where the boundary is. The embodiment of this merging of the real and the mystical is Sia's house: the number of windows varies daily, linen closets open to courtyards, and ascending stairs empty onto a lower floor.

The structure of the novel is organized around Farrell's quest. He enters the novel searching for his lost past, and all events are witnessed by him and seen through his perceptions. Yet the quest is not the grand adventure of epic fantasy, and Farrell's humor and ironic commentary turn the plot into a parody...