This paper reviews first the long controversy that finally led to recognition that dualistic models (North versus South) were no longer suitable for understanding the multi-regional differentiation of contemporary Italian development, since that development had generated a new geo-economic formation labelled as ‘peripheral economy’ or ‘Third Italy’, whose speciific development agent had been small enterprise spatial systems, later named with terms that were newly coined (‘system areas’) or rediscovered (the Marshallian ‘industrial district’). Frorn that point onwards, the Italian as well as the international debates on small enterprise spatial systems (SESSs), and especially on industrial districts, record attitudes oscillating from being passionately in favour to being hypercritical but, in both cases, strongly ideologized. The Third Italy's case supplies a pertinent example of the risk of ideologizing a scientific controversy. Despite the continuing emphasis put on their past performances, the most recent difficulties of the SESSs to cope with post-industrial transition pose the question of whether and to what extent the Third Italy concept can hold its former epistemological and interpretative power. Components and mechanisms of the SESSs currently affected by the post-industrial processes are identified by means of three stylized schemes (the production, spatial and social models of an SESS). A brief overview of the evolution of the Italian regions from 1951-91 supports the assumption that the SESSs have been the dynamic agent of both the genesis and the dissolution of the Third Italy. The conclusions of the paper can be summarized as follows: 1 SESSs, even in their most illustrious form, the industrial district, are concrete geo-historical formations and not abstract timeless constructions to be studied in their processes of genesis, decline and transformation; 2 ideological stereotypes impeded, some two decades ago, the recognition of the specificityof Italian development and, in particular, that of the Third Italy with its SESSs; 3 this ‘distraction’ hindered the timely adoption of appropriate policies; and 4 it would be ironic if an innovative analysis such as that which led to the identificationand the conceptualization of industrial districts and the Third Italy now became a newstereotype. Hence further empirical field research is required which can protect the considerable accumulation of knowledge about small enterprise spatial systems from the risk of becoming an ideological faith far from reality.