Do a rising divorce rate and falling birth rate lead to an increased sense of isolation? Is an only child or single adult inevitably 'alone'? Friendship seems to be the obvious answer to these developments? but has been until now relatively unappreciated in academic research. This volume presents for the first time an introduction to the sociology of friendships, with contributions summarizing basic sociological concepts about friendship and its history, presenting research into friendship relations in practice, and offering insights into current friendship phenomena. And importantly, it also answers a question of great relevance beyond the realms of sociology: What does friendship mean today?