The study of institutions is a long tradition in the history of science, but the ways to study them have yet to be fully examined. This paper offers a critical review of major methodologies developed in the past five decades to investigate institutions and their builders in historical context, and introduces six cases that show the values and difficulties of institutional studies. Institutional history, I contend, is at the crossroads of intellectual history and social history. It thus has affected and been affected by historiographical developments in history of science, such as the internalist-externalist debates, the study of research schools and national styles of science, the rise of laboratory studies, and big science and big organizations.