This book explores teachers' cognitions about the teaching of writing in English as a foreign language (EFL) and their teaching practice, as well as factors influencing the formation and reformation process of their cognition. Taking stock of Bakhtin's dialogism as the theoretical framework, the authors argue that the formation and reformation of teacher cognition is a dialogic process. A systematic analysis of participating teachers' cognition formation and re-formation process suggests the highly individual nature of teachers' cognitions. EFL researchers and teachers, teacher educators, teacher education policymakers, university administrators and EFL textbook writers could draw on the findings of the study to provide better resources to implement the teaching of EFL writing more effectively. The study has adopted a mixed-methods approach, whose quantitative results show the patterns and differences of teacher cognition among teachers of different backgrounds and with different schooling, education and working experiences. The qualitative findings show in detail teachers' cognition formation and reformation processes and the factors contributing to such processes, revealing convergence and divergence of teachers' stated cognitions, with a focus on the discrepancy between teacher cognition and teaching practice. These are useful lenses through which researchers and teachers will find significant implications for offering EFL writing instruction more effectively.