The Routledge Handbook of Language Teacher Action Research. AnneBurns and KenanDikilitaş. Abingdon, England: Routledge, 2025. Pp. Xxi+413.

Action research (AR) is a cyclical process where practitioners identify a problem, plan and implement a solution, observe the results, and reflect to improve practices. As AR is inherently geared toward change and improvement, impact becomes central to its significance. Traditionally defined as the influence, effect, measurable contribution, or benefits arising from research, impact can also be seen as the process by which research knowledge benefits recipients. In structuring this handbook around different dimensions of impact, Burns and Dikilitaş show how inquiry within AR is intrinsically impactful for practitioners. This edited collection explores AR's transformative role in language education, where impact is not just a by‐product but an integral part of knowledge construction, sharing, and application. It underscores AR's suitability for creating meaningful impact and highlights the interconnected processes of inquiry, teaching, and learning. The book is divided into five parts, addressing AR's professional, pedagogical, personal, and educational dimensions, and concludes with reflections from teacher‐researchers working in diverse contexts.