The book behind Fritz Lang's landmark 1927 science-fiction film Metropolis This book is not of today or of the future. It tells of no place. It serves no cause, party or class. It has a moral which grows on the pillar of understanding: The mediator between brain and muscle must be the Heart. , Thea von Harbou, in the novel's original epigraph Originally published in German in 1925, this expressionist epic tells a story about class difference and love in a city that boasts technological growth at the expense of exploited laborers, contending with the relationship between advances in technology and social progress. Written in tandem with the 1927 science-fiction film of the same name, which was directed by Thea von Harbou's husband Fritz Lang, the story, through both the novel and the film, has inspired and influenced countless works of art, creating a legacy that extends across the science-fiction genre and beyond it.