In contemporary natural science, scientific knowledge is created collaboratively in research groups. Therefore, any attempt to understand comprehensively the social dimension of scientific knowledge creation has to account for the epistemic role of research groups. While philosophy has long focused on notions of community to account for epistemologically significant matters of social structure, more recent research in philosophy and social epistemology of science has begun to analyze research groups, choosing either a collectivist or an individualist approach. I pursue an individualist approach to research group collaboration, a decision resonant with the book’s empirical grounding in qualitative data obtained from observation and individual interviewing. Furthermore, I pursue a comparative angle, investigating the differences and similarities of mono- and interdisciplinary group collaboration. The following Chap. 3 will detail the empirical method and the comparative case study that underlie this book.