This is the book which led to the first Science Fiction film of the same name written by Harbou and directed by Fritz Lang. While the film is defiantly a classic, the medium was still in its infancy and some of the techniques of clear and consistent story telling in moving pictures were yet to be developed. In short, I have seen the film several times and while I got the gist of it the story never became fully clear until I read the book.
The book is melodramatic and the theme is a bit difficult to square with Ms. Harbou's eventual association with the National Socialists, but for anyone who wants a richer understanding of the file I would recommend the book.
