The statement above is an understatement. I have since found that Chambers had 14 of his works turned into movies in his lifetime. One of his books, The Common Law, was filmed 3 times. For an updated list and reviews click here.

The restless sex 1918

The Restless Sex (Cosmopolitan Pictures, for Paramount, 1920) - Cast: Marion Davies, Ralph Kellard, Carlyle Blackwell, Charles Lane, Vivian Osborne, Corrine Barker, Edna Rose and Stephen Carr. Directed by Robert Z. Leonard. Scripted by Robert W. Chambers. Story by Frances Marion. 7 Reels.

It looks like he may have written two more movies for Ms. Davies. Two of his books have the same names as movies by Marion Davies;

• The Dark Star - 1919 (The Chambers work of the same title came out in 1917)
  The Dark Star (Cosmopolitan, released through Artcraft/Paramount, 1919) - Cast: Marion Davies, Norman Kerry, DorothyGreen, Matt Moore, Ward Crane, George Cooper, Arthur Earle, Butler Conblough, Emil Hoch, James Laffey,William Brotherhood and Fred Hearn. Directed by Allan Dwan.

  -and-

• Operator 13 - 1934 (Secret Service Operator 13 came out the same year [1 year after Chambers' death] and has the same plot)
  Davies plays an actress who becomes a Union spy during the Civil War and finds herself involved with Confederate he-man Cooper. Based on a real-life story.

  Operator 13 (Cosmopolitan, released through M-G-M, 1934) - Cast: Marion Davies, Gary Cooper, Jean Parker, KatarineAlexander, Ted Healy, Russell Hardie, Henry Wadsworth, Douglas Dumbrille, Willard Robertson, Fuzzy Knight,Sidney Toler, Robert McWade, Walter Long and the four Mills Brothers. Directed by Richard Boleslavsky.

He also wrote the book for another picture, not by Davis, to go with a major motion picture release and may even have had some input since he was a known authority on the Revolutionary War.

America; or, The sacrifice 1924Illustrated with Scenes from the Motion Picture New York Grosset &Dunlap 1924 Photoplay edition issued to coincide with the releaseof the D.W. Griffith directed film epic about the AmericanRevolutionary War starring Neil Hamilton and Carol Dempster.

The tie to Cosmopolitan pictures and Ms. Davies is of interest. That may mean that Chambers spent time at William Randolph Hearst's San Simeon.

Chambers has always traveled with the rich and powerful, we see that in his books. That he knew Rupert Hughes, the uncle of Howard Hughes, is a fact. Rupert Hughes wrote the 1938 introduction to the re-issue of The King in Yellow. We also know that he wrote at least one, if not 3 pictures for Davies. That seems like hanging with the rich and powerful to me.

The movie Pickets, from a short story appearing in The Haunts of Men, F. A. Stokes Co., N. Y., 1898 was