The School of Hard Knocks is an idiomatic phrase referring to the inadvertent education one receives from negative experiences in life, often contrasted with formal education. The term originated in the United States; its earliest documented use was in 1870 in the book The Men Who Advertise:"... his misfortunes were largely owing to the inexperience of youth. Trained, however, in the school of hard knocks, he now had learned the theory of success".