An employment contract or contract of employment is a kind of contract used in labour law to attribute rights and responsibilities between parties to a bargain. The contract is between an "employee" and an "employer". It has arisen out of the old master-servant law, used before the 20th century. But generally, the contract of employment denotes a relationship of economic dependence and social subordination. In the words of the controversial labour lawyer Sir Otto Kahn-Freund,