Dale Breckenridge Carnegie (originally Carnagey until 1922 and possibly somewhat later) (November 24, 1888 to November 1, 1955) was an American writer and lecturer and the developer of famous courses in self-improvement, salesmanship, corporate training, public speaking and interpersonal skills. Born in poverty on a farm in Missouri, he was the author of How to Win Friends and Influence People, first published in 1936, a massive bestseller that remains popular today. He also wrote a biography of Abraham Lincoln, titled Lincoln the Unknown, as well as several other books.

Carnegie was an early proponent of what is now called responsibility assumption, although this only appears minutely in his written work. One of the core ideas in his books is that it is possible to change other peoples behavior by changing ones reaction to them.

Born in 1888 in Maryville, Missouri, Carnegie was a poor farmers boy, the second son of James William Carnagey and wife Amanda Elizabeth Harbison (b. Missouri, February 1858  living 1910). In his teens, though still having to get up at 4 a.m. every day to milk his parents cows, he managed to get educated at the State Teachers College in Warrensburg. His first job after college was selling correspondence courses to ranchers; then he moved on to selling bacon, soap and lard for Armour & Company. He was successful to the point of making his sales territory of South Omaha, Nebraska the national leader for the firm.

After saving $500, Carnegie quit sales in 1911 in order to pursue a lifelong dream of becoming a Chautauqua lecturer. He ended up instead attending the American Academy of Dramatic Arts in New York, but found little success as an actor, though it is written that he played the role of Dr. Hartley in a road show of Polly of the Circus. When the production ended, he returned to New York, unemployed, nearly broke, and living at the YMCA on 125th Street.