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.
The Adventure of Sherlock Holmes' Smarter Brother accompanied by a disguised Sherlock and Watson. Wilder was having lunch with producer Roth when it was suggested that Wilder spoof Sherlock Holmes. Roth approached Wilder again a week later and inquired if Wilder had given any more thought to the idea of a Sherlock Holmes film. Wilder replied "No, but I have given a great deal of thought to Sherlock's insanely jealous brother Sigi." In his autobiography, Wilder explained that he was further motivated by the experience of working with his "Young Frankenstein" co-stars Madeline Kahn and Marty Feldman and he wanted to write parts for both of them