The book presents a series of empirical, historical and theoretical studies that interrogate the unity, diversity and novelty of interdisciplinary research, cutting across the boundaries between the natural sciences and engineering and the social sciences, arts and humanities. It interrogates the claim that interdisciplinary research involving social scientists and/or artists, as well as scientists contributes to the democratization of expertise, helping to forge, what Michel Callon has termed, 'hybrid fora' spaces in which non-experts as well as experts can play a critical role in scientific controversies. The collection focuses in on two fields, anthropology and geography, which have historically been internally divided between social and natural scientific sub-fields. It is in these disciplines, in particular, that the question of the connections between the natural and social sciences, or the lack thereof, has most consistently been posed.