Introduction -- The empirical puzzle: the post-industrial divergence of Allentown and Youngstown -- Historical antecedents : the emergence and divergence of regional social structures, 1743-1945 -- Two critical choices : invoking social structure in crises -- How Allentown got its groove back :...

Dense social networks are thought to be a pre-requisite for innovation-led economic growth and, as a result, building socalled "knowledge networks" has become an important goal for some policy-makers. This has certainly been the case among "rust belt" communities where innovation and economic...