– attributed to Sherlock Holmes

The very phrase brings to mind Sir Arthur Conan Doyles’s creation, Sherlock Holmes – most famous detective of all time. Yet nowhere in any of Conan Doyle’s books does Holmes ever utter the oft-quoted words.
The closest Holmes comes to saying it is in the story “The Crooked Man,” published in the Strand Magazine in 1893 and later included in “The Memoirs of Sherlock Holmes,” published in 1894.
In the story, Dr. Watson, Holmes’s former assistant, has gotten married and no longer lives at Holmes’s flat at 221B Baker Street, London. When Holmes calls on Watson to ask for his help in solving a mystery, he makes a few deductions about his old friend. He observes, for example, that Watson still smokes the same pipe tobacco – from the ash on his coat – and that he is very busy.
Watson asks how he knows this. Holmes says that Watson takes a Hansom cab when he is busy and walks when he is not. Watson’s boots are dusty enough to have been walking; therefore, Holmes says, he must have taken a Hansom. Therefore, he must be busy.
‘Excellent!’ Watson says.
‘Elementary,’ says Holmes.



Basil Rathbone & Nigel Bruce as Sherlock Holmes & Watson in the 1939 film series.



Robert Downey Jr. & Jude Law as Sherlock Holmes & Watson in the movie "Sherlock Holmes" 2009