What happens at the point of interchange between scholarly communities? We examine this question by investigating the case of growing ties between historical sociology and ethnography, two social scientific methods that once seemed to have little in common. Drawing on methodological writings by ethnographers and original interviews with practicing historical sociologists, we argue that these ties have been shaped by structural and methodological homologies between the two disciplines. Structurally, ethnography and historical sociology are similarly positioned in sociology more broadly, as enterprises with sometimes-tense relationships with dominant assumptions of the social sciences. Methodologically, both ethnographers and historical sociologists face the challenges of bounding the research process, navigating access to data, analyzing and retaining data while “in the field,” and overcoming cultural distance between themselves and the worlds they are studying. Taken together, these findings extend work in the sociology of science and knowledge and suggest some key conditions for intellectual efflorescence.