Kerstin Kallass systematically examines the heterogeneous processes of collaborative writing in Wikipedia for the first time, based on a linguistic text and writing process analysis. This enables the author to gain an understanding of the complex nature of writing in collaborative online contexts. Using selected articles as examples, she explores aspects such as article initiations, individual and collective action patterns, planning, structuring, and evaluation processes, as well as controversies, edit wars, and vandalism. In particular, controversies emerge as a form that has been overlooked in writing research, which not only affects the writing processes in Wikipedia but also has implications for the entire constitution of knowledge, thus appearing as a fundamental component of collaborative writing.