This chapter examines several ways of communicating threats, the various types of threats, and the problems raised in their communication. The problem of communicating the threat to the adversary and convincing him of the determination to implement it assumes great importance in nuclear strategy. An explicit threat may come from an official source, or it may be leaked through an unofficial source. An official threat appears in numerous forms: official announcements by leaders and political figures, policy decisions, official broadcasts, and pacts and treaties in which various commitments are undertaken. The explicit threat, in which the threatener announces verbally what action he seeks to prevent, must be distinguished from the indirect, implied threat. A threat may be detailed and specific regarding those actions which will be considered aggressive and will bring about implementation, or it may be general and abstract. The most convincing way to convey a threat is through demonstrations of force.