Although social anthropologists themselves live lives in which friendship is probably just as important as kinship, and a good deal more problematic to handle, in our professional writings we dwell at length upon kinship and have much less to say about friendship. I venture upon this article with a large measure of disbelief at anthropologists' efforts to uncover friendship. The meagre attention it has received seems to be a function of the formal traditions of our discipline, as much as anything else. For example, where we observe behaviour in the field between persons who are known to us to be cousins, we are very likely to analyse this behaviour in our writings as 'cousin behaviour'; but it may be no such thing; rather, it may be behaviour between friends. Significantly, socio-anthropological studies undertaken by someone whose formal training was not within the discipline (e.g. Laurence Wylie's (1957) monograph on the Vaucluse) and autobiographies by the anthropologists' 'primitives' themselves (e.g. Baba of Karo recorded by Mrs Mary Smith (I964)) frequently devote a good deal of attention to friendship, both as an intrinsic value of human life and as one woven into the fabric of kinship, economics and politics. However, I also believe that there are no short cuts in the comparative sociology of friendship. To begin with, we have to think hard about what we mean by the word 'friendship' when we use it; as Pitt-Rivers remarks in another connexion 'let us examine the objective status of the terms in which the quality of interpersonal relations are described' (I96I: I 8i). Secondly, the tradition of structural analysis in our discipline is surely indispensable when trying to compare the nature and function of friendship with those of other interpersonal relations to which it is close in one way or another. These are the two objectives of this article. Their explication leaves space for only a preliminary and partial treatment of crosscultural differences in friendship; instead, the argument proceeds to certain conclusions based on a notion of friendship in our own Western, middle-class culture.