The Elements of Style is a prescriptive American English writing style guide comprising eight "elementary rules of usage", ten "elementary principles of composition", "a few matters of form", a list of forty-nine "words and expressions commonly misused", and a list of fifty-seven "words often misspelled". In 2011, Time magazine listed the writing style-guide as one of the 100 best and most influential books written in English since 1923. Cornell University professor of English William Strunk, Jr., wrote The Elements of Style in 1918, and privately published it in 1919, for in-house use at the university. In The Elements of Style (1918), as a professor of English, William Strunk concentrated on specific questions of usage and the cultivation of good writing with the recommendation "Make every word tell"; hence, the 17th principle of composition is the simple instruction: "Omit needless words."