Based on critical readings of the three main contributions of the special issue and on my own research experiences, the article points out three related features of developmental activity research projects as particularly challenging for the analysis and advancement of cultural-historical activity theory (CHAT). One feature is the nature of the joint developmental project. A second feature is the researchers' role in the joint developmental activity. The third feature is the focus on the transformations of the central artifacts that make up the joint project. Finally, with departure from the stance that developmental activity research projects are propelled by two kinds of practitioners-the practitioners of research and the practitioners of another activity-which may support each other not only in practical matters but also with regard to concepts and perspectives, I consider advancement of CHAT methodology by outlining a beyond-interventionist methodology.