Osmosis is the movement of particles across a boundary until the saturation of particles has been equalized on both sides of the boundary. Although this term is most often used in biology, it is a relevant metaphor for comparative and international education (CIE), as the boundaries which define the field are permeable, with few limitations on what is and is not considered CIE. Previous introductory chapters to the Annual Review of Comparative and International Education have examined the professionalization of the field through the characteristics of articles published in prominent CIE journals. While drawing on a similar framework, this chapter, rather than examining CIE from the inside, examines the development of the field from the outside by considering what, where, and why CIE-related articles appear in journals outside of the field. In addition to data on articles from CIE journals for 2017, education-related articles from domestic and international journals with the highest impact factor from the fields of sociology, political science, economics, anthropology, psychology, and education are also included. These components will provide multiple points of comparison and discussion to examine how non-CIE journals include CIE related topics to identify which themes permeate the CIE boundary.