This chapter defines comparative and international education (CIE), and outlines the broader societal and historical context that connects teacher education to CIE. A historical perspective is deployed for explaining current shifts in the field of CIE. The analysis presented interrogates purposes and conventions in CIE. How CIE matters for the preparation of teachers is best understood in relation to the political agendas CIE has served in the past and the agendas it serves in the contemporary context. The chapter concludes with a discussion on different stances regarding the relationship of research to practice that the author encountered in her research on teacher education and in her work with experts in teacher training and education development, in the past few years. [For the complete volume, "Annual Review of Comparative and International Education 2018. International Perspectives on Education and Society. Volume 37," see ED667018.]