His Last Bow: The War Service of Sherlock Holmes, later titled "His Last Bow: An Epilogue of Sherlock Holmes", is one of 56 short stories about Sherlock Holmes written by Sir Arthur Conan Doyle. It was first published in September 1917 in Strand Magazine, and, amongst six other stories, was collected in an anthology titled His Last Bow: Some Reminiscences of Sherlock Holmes. The narration is in the third person, instead of the first person narration usually provided by the character of Dr. Watson, and it is a spy story, rather than a detective mystery. Due to its portrayal of British and German spies, its publication during the First World War and its patriotic themes, the story has been interpreted as a propaganda tool intended to boost morale for British readers.

On the eve of the First World War, the German agent Von Bork is getting ready to leave England with his vast collection of intelligence, gathered over a four-year period. His wife and household have already left Harwich for Flushing in the Netherlands, leaving only him and his elderly housekeeper. Von Bork's associate, Baron von Herling, is impressed by his acquisition of vital British military secrets, and tells Von Bork that he will be received in Berlin as a hero. Von Bork says that he is waiting for one last transaction with his Irish-American informant, Altamont, who will arrive shortly with a rich treasure: naval signals.