Activity theory is an interdisciplinary approach to human sciences that originates in the cultural-historical psychology school, initiated by vygotsky, leont'ev, and luria. It takes the object-oriented, artifact-mediated collective activity system as its unit of analysis, thus bridging the gulf between the individual subject and the societal structure. This 1999 volume includes 26 chapters on activity theory by authors from ten countries. In part i of the book, central theoretical issues are discussed from different points of view. Some topics addressed in this part are epistemology, methodology, and the relationship between biological and cultural factors. Part ii is devoted to the acquisition and development of language. This part includes a chapter that analyzes writing activity in japanese classrooms, and a case study of literacy skills of a man with cerebral palsy. Part iii contains chapters on play, learning, and education, and part iv addresses the meaning of technology and the development of work activities. The final part covers issues of therapy and addiction.