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.
Mycroft Holmes in "The Greek Interpreter", his blundering approach to the case nearly costs the client his life. Mycroft resembles Sherlock, but is described in "The Greek Interpreter" as being "a much larger and stouter man". In "The Bruce-Partington Plans", the following description is given: Mycroft spends most of his time at the Diogenes Club, which he co-founded. He is the only character to refer to Sherlock exclusively by his first name. Mycroft Holmes has been portrayed many times in film, television, and radio adaptations of the Holmes stories. The character has been used many times in works that are not adaptations