Henry Williamson's "The Patriot's Progress" references the title of "The Pilgrim's Progress" and the symbolic nature of John Bunyan's work. The protagonist of the semi-autobiographical novel is John Bullock, the quintessential English soldier during World War I. The character of Billy Pilgrim in Kurt Vonnegut's novel, "Slaughterhouse-5: The Children's Crusade", is a clear homage to a similar journey to enlightenment experienced by Christian, although Billy's journey leads him to an existential acceptance of life and of a fatalist human condition. Vonnegut's parallel to "The Pilgrim's Progress" is deliberate and evident in Billy's surname. Charlotte Brontë refers to "Pilgrim's Progress" in most of her novels, including "Jane Eyre", "Shirley", and "Villette". Her alterations to the quest-narrative have led to much critical interest, particular with the ending of "Jane Eyre". Walt Willis and Bob Shaw's classic science fiction fan novelette, "The Enchanted Duplicator", is explicitly modeled on "The Pilgrim's Progress" and has been repeatedly reprinted over the decades since its first appearance in 1954: in professional publications, in fanzines, and as a monograph. Enid Blyton wrote "The Land of Far Beyond" (1942) as a children's version of "The Pilgrim's Progress". John Steinbeck's novel "The Grapes of Wrath" mentions "The Pilgrim's Progress" as one of an (anonymous) character's favorite books. Steinbeck's novel was itself an allegorical spiritual journey by Tom Joad through America during the Great Depression, and often made Christian allusions to sacrifice and redemption in a world of social injustice. The book was commonly referenced in African American slave narratives, such as "Running a Thousand Miles for Freedom" by Ellen and William Craft, to emphasize the moral and religious implications of slavery. Hannah Hurnard's novel "Hinds' Feet on High Places" (1955) uses a similar allegorical structure to "The Pilgrim's Progress" and takes Bunyan's character Much-Afraid as its protagonist. In Lois McMaster Bujold's "The Borders of Infinity" (1989), Miles Vorkosigan uses half a page torn from "The Pilgrim's Progress" as a coded message to his fleet to rescue him and 9,000 others from a POW camp. Sir Walter Scott uses Bunyan's tale in chapter 32 of his novel "The Heart of Midlothian" (1818) to illustrate the relationship between Madge Wildfire and Jeanie Deans.