who have previously written about the postwar development of naval digital systems in their respective countries.Senior naval officers adopted the phrase The Information Age in 1991, using it to introduce the Copernicus concept for radical change in communications and information architectures. 1 This reinforces the point that information (though not necessarily digitally formatted) is the essential commodity, but that sharing it is the key to effective Command & Control (C2). The early (military) systems also underpinned later civil developments. Driven by a critical needThe article focuses on naval technical developments, across the period 1945-1970 in the United Kingdom, Canada, and the United States.for a new form of high-speed computation and information handling, these early digitized Naval C2 systems were some of the first initiators of the Information Age. This article sets the overall chronology; the wartime spirit of cooperation was initially followed by competition, with each country working in semi-isolation, to preserve its own advantage. Gradually, this was replaced by renewed cooperation, especially when the three sought to implement a common tactical data link (TDL).This article focuses on naval technical developments, across the period 1945-1970 in the United Kingdom, Canada, and the United States. It primarily