This special issue of History of the Humane Sciences intends to shed light on a series of psychopathological entities that do not target well defined conditions and experiences, but rather aim at delimiting zones of uncertainty that defy psychopathology’s order of things: mild diagnoses or subthreshold disorders, borderline conditions, culture bound syndromes, or ideas of dimensions and dimensionality. While these categories have come to play an increasingly central role in psychiatric and psychological thinking during the last 50 years, historians and (...) social scientists have had remarkably little to say about how they have been created, what they have been used for, and what kind of realities they have helped to shape. In this introductory article we propose the concept of ‘psychopathological fringes’ to refer to these categories that are located somewhere at the border of psychopathological classifications and refer to zones of conceptual underdetermination. The notion of fringes serves to highlight both the conceptually and the socially marginal nature of the conditions, personal identities, and worlds delimited by these categories. The fringes of psychopathology are zones of vagueness, of epistemic uncertainty, and moral ambiguity. This introduction proposes a first incursion in these zones. It suggests some of the reason why they might have had attracted little interest in the past and why they may be more salient recently. It follows some analytical clues that might help chart a way through it and proposes a map through the collection of articles included in this issue. (shrink)