The sets and their finish, architecture, custom, costume, haberdashery, language, dialect, grooming, common sense and sensibility all encapsulate neatly in formulaic range on this period acetate, required viewing for every aspiring James Bond. The popular novel in it, the ancient art of acting and the modern stage intersect in subtle transition from their hitherto ritualistic traditional forms to progress ever so slightly with science [in this study of human psychological science in the form of hypnotism, aided by drugs in the form of cannabis japonica -- marijuana], heralded by the modern Socratic iconoclast of rational method [Sherlock Holmes] and his arch nemesis [Professor James Moriarty]. In it, a man in a smoking jacket might morph into dutiful doctor making a house call. The housekeeper might wear an apron, and the valet defer as Sherlock plays highland tunes on his violin with Nero's apparent nonchalance. Having a bath drawn or a buggy called would seem as apropriate as a woman smoking in an evening frock with her hair arranged might seem a bit forward -- or progressive. Was that tobacco early product placement or advertisment? Foiled in the end, Moriarty conveniently escapes [again, having been mentioned early on as the swinging victim of justice on the gallows in Montevideo, Uruguay] in a risky ploy which backfires to become an apparent suicide, when we all know that at some future time when we least suspect it [smile! - like a Star Trek episode] he will return -- quite well, indeed. As all others, please presume this episode to be essential -- as in -- elementary.