Interdisciplinarity is among the most talked about but most misunderstood topics in education on all levels today. Seen as the savior of research and teaching, especially in universities, and of society, or the seeds of destruction, interdisciplinarity's proponents and critics talk past each other. Seldom do they seek common terms; typically, they mean very different approaches when they refer to interdisciplinarity. They erroneously dichotomize disciplines and interdisciplines, confuse specialization and synthesis, and misconstrue “integration.” They also date the historical turn to interdisciplinarity too late. This article critically reviews the history, historiography, and sociology of knowledge of interdisciplinarity with a focus on etiology, epistemology, definitions, relationships among and between disciplines, intellectual and institutional locations, and the organization of knowledge. A new, more historical approach to the “problem” of interdisciplinarity is proposed.