Time was you couldn't swing a cat without hitting an Edgar Wallace book. Wallace (1875-1932) wrote over 170 novels, 975 short stories, and 18 stage plays, as well as a boatload of journalisn, screenplays, poetry, and non-fiction. His publisher once claimed that fully one quarter of all books read in England were written by Wallace -- a claim that might well be true. He created The Four Just Men, Sanders of the River, Mr. J. G. Reeder, and wrote (shortly before his death) the first draft of the script for King Kong. Wallace was once dubbed the most popular thriller writer of the Twentieth Century.
That was then.
Today few people remember him. From 1959 to 1972, Germany's motion picture industry produced almost three dozen very popular "krimis" based on Wallace's thrillers, many of which are available on-line but -- alas -- are not translated or subtitled. From 1960 through 1965, Britain produced an amazing 42 films in its Edgar Wallace Mysteries series. To date, over 160 films have been made based on Wallace's work.
One of those films is 1940's The Case of the Frightened Lady, based on Wallace's 1931 stage play which, in turn, he novelized in 1933. It's a pretty good flick.