A cease and desist letter is a document sent to an individual or business to stop attempted illegal activity ("cease") and not to restart it ("desist"). The letter may warn to the individual or business that if they do not stop certain behaviour by deadlines set in the letter, then that individual or business may be sued. The same letter may also warn the individual or business to take specified actions in order to avoid being sued. When a cease and desist letter is issued by a public authority, it is called a "cease and desist order".