Research on interdisciplinary fields has mainly focused on knowledge production -- the creation of new ideas -- rather than on knowledge socialization, the process by which a scholarly community identifies and teaches a field's core body of knowledge to novices. In this article, we use social network analysis to identify the core knowledge that experts in an interdisciplinary field choose as foundational for students. More specifically, we examine the syllabi of social context of education courses from the top 25 education schools in the United States to determine the shared references, authors, and themes. Our analysis indicates that, perhaps because it is an interdisciplinary field, the social context of education structures core knowledge by shared themes rather than by particular references or authors. We argue that our approach can provide a valuable tool for the study of interdisciplinarity, offering a novel way of understanding the structure and socialization of a field.