This book is the first edited volume to compile up-to-date scholarship that discusses frontier knowledge on second language (L2) collaborative writing (CW) and highlights technology-mediated solutions to it. The volume consists of conceptual papers and empirical studies that explore theoretical, methodological, and pedagogical approaches to CW in face-to-face, online, and hybrid learning contexts. The ten chapters of the book are divided into three sections: (1) theoretical perspectives and a methodological review of CW; (2) empirical research addressing the processes, products, and effects pertaining to CW; (3) pedagogical aspects relevant to CW, namely task design, technology use, and assessment. By examining the implementation of various CW tasks across modes, genres, and L2 learning settings, this book re-evaluates the practices of CW and illustrates how diverse forms of CW can facilitate students’ L2 learning and writing development.