No, no: I never guess. It is a shocking habit, — destructive to the logical faculty.

Arthur Conan Doyle (1859-1930) British writer and physician

Story (1890-02), “The Sign of the Four,” ch. 1 [Holmes], Lippincott’s Monthly Magazine, Vol. 45 (US) / 1 (UK)
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The original publication, and Doyle's manuscript (along with many other iterations across media) use "The Sign of the Four" as the title, while others (including the first book publications) use "The Sign of Four." The five-word form is used most commonly in the story, but the four-word form does show up. (More info.)

Published in novel form as The Sign of Four (1890-10).