In the 1970s, sociologists and political scientists began to develop a notion of "complexity" using concepts from general systems theory and cybernetics and applying them to the fields of social theory as well as policy research and consultation. Social complexity was, however, not just an issue for social scientific theorists. During the period spanning the 1960s and 1970s, the term gained currency across the social sciences as well political and intellectual debates, with theoretical approaches using it not only in its narrow analytical sense but also as an explanatory catchword and metaphor for the era. The project aims to reveal how complexity was presented as an issue and how it became merged into specific policy fields and debates in the USA from the late 1960s through to the early 1980s. An analysis is also made, based on policy programs, on how the perceived complexity was approached. Why did it achieve such academic and political prominence in the 1970s? What did it mean to view society as "complex"? What consequences emerged from the identification of complexity as a problem? What effects did the associated ideas and concepts have on political action up to the Reagan era? Project duration: June 2012 to December 2017.