Retrospective accounts of materials development in the applied linguistics literature speak to the relationship between creativity and textbook writing, but this study forges another path by examining how an expert ELT (English language teaching) textbook writer deploys creativity during ongoing coursebook production. Qualitative content analysis of data collected via concurrent verbalization, during which the author thought aloud while producing textbook chapters, pre- and post-concurrent verbalization interviews, field notes, and a diary record revealed the creativity that characterized her work at both the process and product levels. Creativity ultimately helped her navigate the publishing constraints in place for her project, including appropriateness controls (e.g. taboo topics), and maintain her focus on learning, teaching, product usability, and publication goals. This study reveals how creativity impacts textbook production during unfolding writing sessions, making an empirical contribution to the research field of materials development. It also provides a view of the constraints associated with commercial publishing, showcases the operations of a skilled author, and demonstrates the usefulness of concurrent verbalization to materials development research: contributions relevant to ELT practitioners interested in textbook production.