Without friendship life seems incomplete. It is no accident that the history of Western thought is also a history of friendship: Homer, Plato, and Aristotle; Cicero, Augustine, and Aquinas; Montaigne, Hume, Ferguson, and Smith; and later Nietzsche and Emerson, but also C. S. Lewis and many others make up an illustrious pantheon of thinkers who have contemplated the virtues, ambiguities, and pitfalls of friendship. For that reason it seems odd that friendship should be as underrepresented as it is in sociology. Apart from the extraordinary heterogeneity of the phenomenon, Nedelmann mentions two interconnected reasons for the relative paucity of engagement with friendship in the social sciences: the avoidance of topics to do with "individualistic sentiments' in private life; and a focus on large-scale social structures to the near exclusion of "interactions that are transient and diffuse" (Nedelmann, 1991, my translation). To say that friendship is underrepresented in sociology is to acknowledge that there is work on the topic. This book, after all, draws liberally on existing research, old and new. It is, however, still relatively marginal in the discipline, especially concerning friendship as an intimate relationship between two people. There is a sense that the dyad isn't a "large" enough social relationship to merit serious attention.