"Christmas on Ganymede" is a science fiction short story by American writer Isaac Asimov. It was written in December 1940, first published in the January 1942 issue of Startling Stories, and reprinted in the 1972 collection The Early Asimov and the anthology Christmas on Ganymede and Other Stories, edited by Martin H. Greenberg. It was the twenty-sixth story written by Asimov, and the nineteenth to be published. In his autobiography In Memory Yet Green, Asimov had this to say about Christmas on Ganymede: "I was trying to be funny, of course. I had this terrible urge to be funny, you see, and had already indulged in humor in more than one story. Writing humor, however, is harder than digging ditches. Something can be moderately well written, or moderately suspenseful, or moderately ingenious, and get by in every case. Nothing, however, can be moderately humorous. Something is either funny, or it is not funny at all. There is nothing in between." "Christmas on Ganymede" was later included in an early Foundation Series timeline that was published in Thrilling Wonder Stories along with the story "The Portable Star". Source: Wikipedia (en)