Materials development in TESOL has been gaining popularity as a field of study for the last few decades. TESOL materials research as an area of inquiry includes studies focusing on textbook content (e.g., grammar, cultural representation, and authenticity), consumption (use/adaptation of materials by learners and teachers), and production (design and publication) of materials (Harwood, 2014a,b). Materials production is the most neglected of these three areas of research, although it is considered vital to understand how materials are produced and shaped into textbooks that are used in almost every classroom around the world (Harwood, 2010, 2014b; Tomlinson & Masuhara, 2017:145). The present research draws upon interviews with six authors working for different international publishing houses who spoke about the various constraints associated with authoring global textbooks, which are sold around the world. The authors described constraints associated with publishers' preference for international rather than regional or local materials, tight deadlines, publisher-led rather than author-led models of production, the constraining influence of teacher and market representative feedback on draft materials, and constraints associated with taboo topics debarred from the materials. These formidable constraints reduce the role of authors in decision-making, hindering attempts to create more carefully crafted products, and we suggest that textbook publishers need to reconsider their production processes as part of a drive to enhance the quality of the global textbook.