Participants with teaching and research experience across eight disciplinary areas were introduced to the idea of "threshold concepts" and were then invited to identify potential threshold concepts in their own disciplines through small-scale research activities. Participants conceptualized their involvement in different ways: for some it provided a means of initiating changes in practice at faculty, department or course level, while others couched their involvement in terms of professional development or intellectual curiosity. This article describes how three selected disciplines--Sports Science, English Literature and Engineering--carried out enquiries into threshold concepts, and the ways in which they reflected on their participation in interdisciplinary seminars and disciplinary enquiry. These accounts highlight the importance of promoting a culture in which enquiry and reflection are central, while at the same time recognizing the value of appropriate "points of focus" for these activities and the importance of context-specific ideas of "quality" in practitioner research.