This paper reviews some of the relevant background findings against which the empirical studies reported in this special issue were designed. Particular attention is given to previous findings on the development of children's national knowledge, national attitudes and national identifications. The paper also reviews five existing theories which have been proposed to explain the development of children's intergroup attitudes: cognitive-developmental theory (Aboud, 1988(Aboud, , 2008, social identity development theory (Nesdale, 2004(Nesdale, , 2008, social identity theory (Tajfel, 1978;Tajfel & Turner, 1986), societal-social-cognitive-motivational theory (Barrett, 2007(Barrett, , 2009Barrett & Davis, 2008) and integrative developmental-contextual theory (Bar-Tal & Teichman, 2005;Teichman & Bar-Tal, 2008). The paper concludes by describing the shared methodology which was utilised by all of the following studies that are reported in this special issue. These studies were designed to examine how children's attitudes to other nations develop within a range of different national contexts, some of which have not experienced violent conflict in the recent past (England, The Netherlands) but others of which have recently experienced, or still are experiencing, conflict, violence or warfare (Basque Country, Bosnia, North and South Cyprus, Northern Ireland, Israel).