 Mycroft Holmes, as depicted by Sidney Paget in the Strand Magazine Mycroft Holmes is a fictional character in the stories written by Arthur Conan Doyle. He is the older brother of the famous detective Sherlock Holmes. Possessing deductive powers exceeding even those of his younger brother, Mycroft is nonetheless incapable of the sort of detective work done by Sherlock due to the lack of desire to do the physical work necessary to actually bring cases to their conclusions.
- ...he has no ambition and no energy. He will not even go out of his way to verify his own solutions, and would rather be considered wrong than take the trouble to prove himself right. Again and again I have taken a problem to him, and have received an explanation which has afterwards proved to be the correct one. And yet he was absolutely incapable of working out the practical points...
--Sherlock Holmes, speaking of his brother in "The Adventure of the Greek Interpreter"
While Conan Doyle's stories leave unclear what Mycroft Holmes' exact position is in the British government, Sherlock Holmes says that “occasionally he is the British government . . . the most indispensable man in the country." He apparently serves as a sort of human computer: "The conclusions of every department are passed to him, and he is the central exchange, the clearinghouse, which makes out the balance. All other men are specialists, but his specialism is omniscience" ("The Bruce-Partington Plans").
Mycroft has appeared or been mentioned in at least four stories by Doyle, including "The Greek Interpreter", "The Final Problem", "The Empty House" and "The Bruce-Partington Plans". While he does occasionally exert himself in these stories on the behalf of his brother, he on the whole remains a sedentary problem-solver, providing solutions based on seemingly no evidence and trusting Sherlock to handle any of the practical details.
Mycroft spends most of his time at The Diogenes Club, which he co-founded.
A resemblance has been noted between Mycroft Holmes and another brilliant but sedentary fictional detective, Nero Wolfe; it has been suggested, with varying degrees of seriousness, that they may have been related.
The best-known form of this hypothesis — popularized by William S. Baring-Gould, who wrote "biographies" of both Sherlock Holmes and Nero Wolfe — holds that Wolfe is the offspring of Sherlock and Irene Adler.
Another parallel can be observed in the TV series Monk in the connection between fictional obsessive-compulsive detective Adrian Monk and his even more intelligent, though even more neurotic, brother Ambrose.
Mycroft and the Diogenes Club play an important part in Kim Newman's novel Anno-Dracula.
In Alan Moore's The League of Extraordinary Gentlemen, Mycroft Holmes appears as the leader of British intelligence under the code-name "M" (a reference to Ian Fleming's James Bond novels).
In The Moon Is a Harsh Mistress
In Robert A. Heinlein's novel The Moon Is a Harsh Mistress, the character Mycroft Holmes is a self-aware computer system entrusted with running the life-support systems, among other things, in a penal colony on the Moon or "Luna". The computer, also referred to as "Mike", eventually sides with characters inciting a revolution to free Luna, and is instrumental in their victory against the Lunar Authority on Earth. Mike was a "Highly Optional, Logical, Multi-Evaluating Supervisor" or a HOLMES IV model computer. He adopts a persona as Adam Selene.
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