If you have a contract with someone and they are breaching that contract, a cease and desist letter can be an important tool to use. By sending an effective cease and desist letter, you can inform the other party of the breach, urge them to comply with the contract, and tell them what will happen if they continue to violate it. In many cases, this resolves the situation without the time and costs of a court case. Even if it is unsuccessful, the cease and desist letter prevents the other party from claiming that it was unaware that it was breaking the agreement.