This edited book brings together documented evidence and theoretical propositions on the essential mediating role of digital technology in L2 teacher education and professional development. Topics range from technological affordances in teacher education, to challenges and responses to emergency transition from face to face to virtual professional development, to successful practices of online teacher training courses. Bringing together examples from various countries and contexts of how L2 teacher trainers and trainee teachers view these forced changes and react to them, the volume fills a gap in the use of digital technology in contexts where teacher educators and trainee teachers are not technology-literate and not prepared for technology-oriented education. In addition to a Foreword by Mark Warschauer and Introduction and Conclusion chapters by Editors, the volume features 13 full-length chapters by some of the well-known experts from countries such as Australia, Finland, Mexico, the UK, the USA, Spain, Singapore, Turkey and Sweden.