It's true that
Walter B. Gibson created the pen name "Maxwell Grant" (by combining the names of two magic dealers he knew) and was the first person to use it. Nevertheless, "Maxwell Grant" is a pseudonym that was owned by Street & Smith, the publisher of The Shadow Magazine. Street & Smith hired other writers to pen "The Shadow" stories, but published them all under the name "Maxwell Grant."
This particular movie is based on the story "Foxhound," published in #118 of The Shadow on January 1, 1937. That story was not written by Gibson but by
Theodore A. Tinsley. Tinsley penned a total of 26 stories during the original 1931-1949 run of The Shadow Magazine.
Bruce Elliot wrote 15 of them. Gibson was responsible for the vast majority of the stories, writing a total of 284.
