Trivia / 4:50 from Paddington

• Market-Based Title: The novel was serialised in abridged form in the USA as Eyewitness to Death, published in abridged form in Canada as the slightly different Eye Witness to Death, and then released in the USA as a single book under the title What Mrs. McGillicuddy Saw.
• Science Marches On: Miss Marple's ruse to expose the murderer relies on him assuming the body position similar to that he took during the first murder (done by strangling) by making him try to rescue a choking woman. Should this have happened nowadays, however, it is likely that the murderer would have resorted to abdominal thrusts instead - a method invented by Henry Heimlich in 1974. Then again, Dr. Quimper was looking down her throat and preparing to use forceps to remove the supposed fishbone, so it wasn't really the same situation.
• Working Title: The book was originally planned as 4:54 From Paddington. The title change was sufficiently late that some references to train times within the book weren't updated for the first printing.