One of the insights of the anthropological and historical study of expertise is that expert knowledge does not merely describe its objects of interest; it also helps to constitute them. Taken-for-granted objects of existence•whether the economy, the psyche, race, or the population•are brought into being through contingent and often-overlooked historical processes that shape the very possibility of truth and falsity. In this panel, we bring together scholars who have explored how objects of expertise and intervention take form in old and new problem domains, paying special attention to conceptual formations that come to have the force of 'the real,' and are experienced as such. We approach the topic from a number of directions. First, we explore the commonalities and differences between the cases themselves: what they tell us about the ways in which objects of expert knowledge emerge and are taken up, how concepts work to generate or transform such objects of knowledge, how objects become part of the general scenery of common sense, and how they come to generate effects. Second, we are interested in these projects on methodological and theoretical grounds: What kinds of methodological choices ground such studies? What sorts of analytical sensibilities animate the choice of an object? Can such projects accommodate different philosophical commitments? Finally, we foreground some problems such studies raise for the relationship between truth and responsibility: How does one handle the contingency of expert knowledge and the worlds it helps constitute? How does such contingency resonate with the contemporary moment in which expert knowledge seems to be undergoing a crisis of authority? Does an understanding of the contingency of truth-production undermine the capacity for reasoned action? Or does such awareness help us repair the fragile consensus around authorized knowledge?