[originally posted here at Castalia House]
Double Trouble by Carl Jacobi appeared in the Spring 1945 Issue of Planet Stories. It can be read here at Archive.org.
“When Annabella C. Flowers, that renowned writer of science fiction, visiphoned me at Crater City, Mars, to meet her here[on Callisto], I had thought she was crazy. But Miss Flowers, known to her friends as Grannie Annie, had always been mildly crazy. If you haven’t read her books, you’ve missed something. She’s the author of Lady of the Green Flames, Lady of the Runaway Planet, Lady of the Crimson Space-Beast, and other works of science fiction. Blood-and-thunder as these books are, however, they have one redeeming feature—authenticity of background. Grannie Annie was the original research digger-upper, and when she laid the setting of a yarn on a star of the sixth magnitude, only a transportation-velocity of less than light could prevent her from visiting her “stage” in person.”