This chapter traces the arc of the security dilemma through time. It begins with Thucydides and, stretching through the formal articulation with John Herz, Herbert Butterfield, and Robert Jervis, and continuing through the Cold War. It makes the link to intelligence work, a connection first made by Michael Herman. In particular, it shows how the security dilemma is most potent when there is a strong linkage between intelligence collection and attack, as is the case in cyber operations. This tight linkage makes collection activity more threatening, and is more likely to lead to a response by the involved nations.