3. The Sign of the Four did not sell particularly well either
The second Holmes novel appeared in book form in the late summer of 1890. Like its predecessor, its sales were respectable, but hardly overwhelming. Sales were no doubt suppressed by its appearance, in serial form, in several British magazines throughout the year. These magazines truncated the title in several instances, referring to the work as The Sign of Four. The book edition in Britain and the United States also used the shorter title, and some still do. As in Britain, the American edition did not sell particularly well, and the novel appeared serialized in magazines at the same time the book appeared. Magazine sales were strong on both sides of the Atlantic, indicating a taste for Holmes in smaller doses.
The second novel includes the introduction of another Holmesian character, Mary Morstan, to whom Dr. Watson proposes marriage. Her acceptance near the end of the novel indicates that the brief partnership between Watson and Holmes would not last. As a married man, and a physician, Watson would leave their shared quarters in Baker Street. Some have speculated Doyle was already wearying of the detective he created, based on the ending of the second novel. He expressed the wish to work on other forms of stories, including historical fiction. By then, Doyle resided in London, with an office in Upper Wimpole Street, and a new commission for Holmes stories in short form from The Strand Magazine.