Usually introduced as the forgotten member of sociology's 'big four' (the other ones being Marx, Weber and Durkheim, remember?), Simmel was rather like Gary Barlow out of Take That, the one that had all the good ideas and did all the work but none of the fans fancied or could remember what he looked like (for those over 25 or under 18, Take That were a brief flash in the pan pretty-boy band that gave us Robbie Williams). Briefly popular in American sociological circles as 'the German who wasn't Marx', Simmel wrote about some of the most pressing issues in the modern world: the function of money; (External Link) the fate of individual identity in city life; and the fear of the outsider that pervades European society. Not so irrelevant after all?