This introduction lays out the book’s central problem: how to account for the historical interaction between twentieth-century political thought and the philosophy of science when the historiography of each of these domains has become so thoroughly specialized. It then introduces a novel methodology based on discursive networks as a way of addressing this problem. Specifically, the discursive network that links epistemology and political thought in interwar Germany and Austria can be mapped onto three distinct planes of articulation, corresponding to three types of well-articulated conceptual relationship: (1) explicit critiques of one thinker by another on the basis of a given concept; (2) explicit affirmations of influence of one thinker upon another, again on the basis of a given concept; and (3) rigorous, formal and demonstrable analogies between the conceptions of two or more thinkers, even where no communication is evident. The key insight upon which this approach relies is that the iteration of complex concepts—those which can only be mapped as multi-dimensional diagrams—is much less likely to be the product of chance than the iteration of simple ones. The upshot is that any time we find well-articulated, complex conceptual parallels emerging between otherwise distinct domains of thought, the reason for this symmetry is bound to be of historical interest.