@HarryT: There was an ill-fated
spelling reform in Germany in 1996 that most notably changed the spelling of the German ß [=ss] digraph. (It's still there, but it's used in fewer words.)
You can easily tell pre-1996 books apart from more recent books by looking for "daß" [= that (conj.)]. If you see "daß," the book was most likely originally published before 1996. (Post-1996 books use "dass.")