This paper discusses theoretical issues linked to the study of identities a
nd intergroup relations within multicultural societies. The issues discusse
d concern how identities acquire meaning in contemporary societies where ev
ents in the social context challenge identities and redefine the boundaries
of the social groups. More specifically the processes involved in the form
ation of new identity categorisations and the structure of identity are dis
cussed. Two arguments are developed. Firstly that within multicultural soci
eties one should study the systems of categorisation and the new psychologi
cal boundaries within the wider theories about the world people elaborate a
nd share. Secondly, it is argued that since people's identities reflect soc
ial relationships, elements of the structure of common identities might be
shared. Finally, the contributions of the papers of this special issue to t
he above theoretical debate are presented. Copyright (C) 2000 John Wiley &
Sons, Ltd.