Cease and desist

A cease and desist letter, also known as "infringement letter" or "demand letter," is a document sent to an individual or business to halt purportedly unlawful activity ("cease") and not take it up again later ("desist"). The letter may warn that if the recipient by deadlines set in the letter does not cease and desist specified conduct, or take certain actions, that party may be sued.

Although cease and desist letters are not exclusively used in the area of intellectual property, such letters "are frequently utilized in disputes concerning intellectual property and represent an important feature of the intellectual property law landscape." The holder of an intellectual property right such as a copyrighted work, a trademark, or a patent, may send the cease and desist letter to inform a third party "of the right holders' rights, identity, and intentions to enforce the rights." The letter may merely contain a licensing offer, or may be an explicit threat of a lawsuit. A cease and desist letter often triggers licensing negotiations, and is a frequent first step towards litigation.