linguistic:paraphrasing, information:classification
"Elementary, my dear Watson"

The phrase "Elementary, my dear Watson" has become one of the most quoted and iconic aspects of the character. However, although Holmes often observes that his conclusions are "elementary", and occasionally calls Watson "my dear Watson", the phrase "Elementary, my dear Watson" is never uttered in any of the sixty stories by Conan Doyle. One of the nearest approximations of the phrase appears in " The Adventure of the Crooked Man " (1893) when Holmes explains a deduction: " ' Excellent!' I cried. 'Elementary,' said he."

William Gillette is widely considered to have originated the phrase with the formulation, "Oh, this is elementary, my dear fellow", allegedly in his 1899 play Sherlock Holmes. However, the script was revised numerous times over the course of some three decades of revivals and publications, and the phrase is present in some versions of the script, but not others. The appearance of the line "Elementary, my dear Potson" in a Sherlock Holmes parody from 1901 has led some authors to speculate that, rather than this being an incidental formulation, the parodist drew upon an already well-established occurrences of "Elementary, my dear Watson."

The exact phrase, as well as close variants, can be seen in newspaper and journal articles as early as 1909. It was also used by P. G. Wodehouse in his novel Psmith, Journalist, which was first serialised in The Captain magazine between October 1909 and February 1910; the phrase occurred in the January 1910 instalment. The phrase became familiar with the American public in part due to its use in the Rathbone-Bruce series of films from 1939 to 1946.