This special issue presents a variety of contemporary perspectives on a key concept of activity theory-the object of activity. The concept of the object of activity has been regarded as one of the most fundamental notions of the approach as a whole, playing an increasingly important role in theoretical developments and practical applications of activity theory. These papers serve to further develop the idea in terms of the relationship between psychological and sociological interpretations, as well as how the object of activity can be used both theoretically and empirically. The articles, based on presentations at two symposia, provide arguments on how to make sense of the concept while indicating potential directions for further development. Contributors to the issue vary in their areas of interest, lending a range of perspectives to the analysis of contemporary activity theory.