More properly called a demand letter.
Such a letter, which is usually signed and dated in the event it is needed later as evidence, demands of the recipient that he, she or a corporate entity, stop and do not resume (cease and desist or terminate absolutely)certain actions which, the letter aleges, asserts legal rights not belonging to the recipient or belonging to other parties; usually the signatory or the principal of the signatory.
A person whose legal rights are being used without authority may opt to litigate immediately but a cease and desist letter can achieve several tactical purposes. First of all, it may stop the illegal misuse of legal rights and if not much damages have been caused, there may then be no need to litigate. Secondly, it publicizes the author's rights proventing the person whom it is alleged is in violation of the author's rights to state that she was unaware of the assertion of legal rights. Thirdly, it often invites the person aleged to be in violation of legal rights to assert on what basis they do so.
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