The ambiguous material identity of nanotechnology is a minor mystery of the history of contemporary science. This paper argues that nanotechnology functioned primarily in discourses of social, not physical or biological science, the problematic knowledge at stake concerning the economic value of state-supported basic science. The politics of taxonomy in the United States Department of Energy’s Office of Basic Energy Sciences in the 1990s reveals how scientists invoked the term as one of several competing and equally valid candidates for reframing (...) materials sciences in ways believed consonant with the political tenor of the time. The resulting loss of conceptual clarity in the sociology of science traces ultimately to the struggle to bridge the disjunction between the promissory economy of federal basic science and the industrial economy, manifested in attempts to reconcile the precepts of linearity and interdisciplinarity in changing socio-economic conditions over a half century. (shrink)