W. Ryerson Johnson (October 19, 1901 – May 24, 1995) is credited with authoring three Doc Savage novels: Land of Always-Night, The Fantastic Island, and The Motion Menace. For the last novel, Johnson supplied the idea for the story, but the novel was written by Lester Dent.

Walter Ryerson Johnson, 1920
W. Ryerson Johnson (October 19, 1901 – May 24, 1995) is credited with authoring three Doc Savage novels: Land of Always-Night, The Fantastic Island, and The Motion Menace. For the last novel, Johnson supplied the idea for the story, but the novel was written by Lester Dent.
I am belgian reader of Doc and I think that Johnson wrote too few : the land of always-night is one of the best Doc I read in french.