What is the theme in Stardust by Neil Gaiman?

Desire is a theme in this story. The first mention of someone's heart's desire takes place when Dunstan Thorn lets his cottage to a man visiting Wall for the Faerie Market. Dunstan is rewarded for his kindness when the man tells him that he will attain his heart's desire the following day at the fair. Dunstan to this point in life had been a stead-fast, practical sort, and generally did not believe in the mysteries that the fair brought with it every nine years.