Historically, the link between the (modern) information infrastructure and national security was first forged in the military domain. More than 60 years ago, the precursors of computers played a considerable role in the race to break military code systems during the Second World War (Kahn 1996; Hinsely and Stripp 2001). The invention of the radio has also had a big impact on military affairs (Berkowitz 2003). The biggest difference to the contemporary cyberthreats debate is, however, that information technology (IT) was predominantly treated as a force enabler rather than a source of vulnerability, so that no effort at threat framing is discernible until the 1980s. In the context of this book, it is nonetheless important to note that the link between information infrastructures and national security was firmly established in military writings after the Second World War (see, for example, Rona 1976; Bellin and Champan 1987; Hables Gray 1997), so that the connection between the two topics became an accepted part of military thinking. On these grounds, the issue met with little resistance in the early 1990s, when it rose to prominence as one of the prime issues in US strategic thinking. These early developments in the military domain are the focus of the first sub-chapter.