Dr. Yen Sin (1936 magazine)

Dr. Yen Sin is a three-issue fiction anthology magazine that was originally published from May through October 1936 by Popular Publications, featuring lead stories by Donald E. Keyhoe about the plots of the titular doctor, a Fu Manchu-type character and mastermind of the "Invisible Empire", and his adversary Michael Traile, "the Man Who Never Slept" (or "Man Who Never Sleeps"), a spy who suffered chronic insomnolence from childhood after an operation to repair a skull fracture caused irreparable brain damage. The magazine was a follow-up to the earlier title The Mysterious Wu Fang by the same publisher that had ended in February 1936.

#1, May & June 1936

 * Note to Our Readers - An Introduction
 * Keyhoe, Donald E., The Mystery of the Dragon's Shadow
 * Gruber, Frank, Slant-Eyed Satan
 * Oboler, Archie, The Night of Ka-Sam
 * Pangborn, Arden X., The Ring of the Red Rooster

#2, July & Aug. 1936

 * Feng Tai Sui Feng
 * Keyhoe, Donald E., The Mystery of the Golden Skull
 * Tudury, Moran, The Third Yen
 * Cameron, Don, Chinatown Scoop
 * Pangborn, Arden X., Death of a Thousand Cuts

#3, Sept. & Oct. 1936

 * Fei Lu Fei Ma
 * Keyhoe, Donald E., The Mystery of the Singing Mummies
 * Norton, Alden, The Seventh Sleeping Brother
 * Gruber, Frank, The Choking Chalice

#4, Unpublished
A fourth issue was solicited, promising a new Keyhoe story, The Case of the Faceless Men, but this was never published, as the magazine ceased publication after the third issue.