Mark Twain's posthumously published story "No. 44, The Mysterious Stranger"—a bizarre tale of supernatural and dreamlike events that take place at the dawn of the age of modern printing in Europe—is the last major work of fiction by one of the greatest American authors of the nineteenth century.

"No. 44, The Mysterious Stranger" is narrated by August Feldner, a sixteen-year-old printer's apprentice living in a remote Austrian village in the late fifteenth century. The print shop in which he works is located in a run-down old castle, which houses over a dozen people, including the print master, his family, and the various men who work in the shop, as well as a magician. August relates the magical events that occur in the castle after the arrival of a strange boy who says his name is "Number 44, New Series 864,962." Twain's central themes in this story include dreams and the imagination, as well as ideas, knowledge, and thought.

The publishing history of Twain's "No. 44, The Mysterious Stranger," subtitled "Being an Ancient Tale Found in a Jug, and Freely Translated from the Jug," is almost as interesting as the story itself. In 1916, six years after his death, Twain's editors published a story entitled "The Mysterious Stranger," which they attributed to Twain's authorship. However, it was discovered during the 1960s that the story as it was originally published had been significantly altered by the editors in a manner that was clearly not Twain's intent. Thus, the story that passed for "The Mysterious Stranger" for over 50 years is now considered to be illegitimate. In 1969, the authoritative version of the story, "No. 44, The Mysterious Stranger," based on Twain's original manuscript, was published for the first time. The following entry is based on a reading of the latter version of the story, which will be referred to in shorthand as "The Mysterious Stranger."