Quasi-Contract
This chapter traces the history of what used to be called quasi-contract but is now part of the law of restitution. It was principally concerned with the receipt of money which belonged in justice to someone else. The earliest relevant action was account, at first limited to agents and then extended to all receivers of money; this was an impracticable action and went into disuse. Actions on the case came to the rescue, particularly the action for money had and received (a species of indebitatus assumpsit). The latter action was used not only in traditional cases of accountability but also where money was received by mistake or compulsion, where income from property was taken by an interloper, or where a party to a failed contract sought rescission. Much of the history is hidden from view by fictions, but Lord Mansfield declared a general principle based on the equity of the common law.