The Adventure of the Greek Interpreter Sherlock Holmes, far from being a one-off in terms of his powers of observation and deductive reasoning, in fact has an elder brother whose skills, or so Holmes claims, outstrip even his own. As a consequence of this, Watson becomes acquainted with the Diogenes Club and his friend's brother, Mycroft. Mycroft, as Watson learns, does not have the energy of his younger brother and as a consequence is incapable of using his great skills for detective work: In spite of his inertia, the elder Holmes has often delivered the correct answer to a problem that Sherlock has brought to him.
Diogenes Club writers developed and used the idea that the club was founded as a front for the British secret service. This may have its root in "The Adventure of the Bruce-Partington Plans", in which Mycroft Holmes is revealed to be the supreme and indispensable brain-trust behind the British government, who pieces together collective government secrets and offers advice on the best way to act. The idea was popularised by "The Private Life of Sherlock Holmes" (1970), a 1970s motion picture directed by Billy Wilder, and has since been frequently used in pastiches of Conan Doyle's stories as well as the TV