This volume provides a distinctive overview and analysis of the place of social constructionism in social psychology. The author's arguments revolve around two key questions: How can social constructionism account for changes in human identities? In what ways might social constructionism accommodate a role for nonhumans - whether technological or `natural' - in the constitution of identity? Michael locates these questions between recent innovations in social psychology and the highly influential contributions of actor-network theory, which has come to dominate the sociology of scientific knowledge.