After reviewing the literature, both academic and nonacademic (e.g., popular media), it has become obvious to me that loneliness is an inherent part of the human condition. Most likely, every person experiences loneliness at some time during the course of his or her life, at least in a transient form. Moreover, loneliness appears to be a cross-cultural phenomena, one identified and examined in an array of countries: Australia (e.g., Renshaw & Brown, 1992), Canada (e.g., Boivin, Hymel, & Bukowski, 1995), Belgium (e.g., Marcoen & Brumagne, 1985), Israel (Margalit & Ben-Dov, in press), and the United States (Cassidy & Asher, 1992). The universality of loneliness may well arise, as Baumeister and Leary's (1995) theory implies, from the universal need for belongingness – the need to establish stable social bonds with others who care. In that context, loneliness is the cognitive and affective reaction to the threat to social bonds. Indeed, loneliness has been regarded in the literature as comprising two related components: (a) a cognitive component, comprising the discrepancy between desired social relationships and actual social relationships, either quantitatively or qualitatively, and (b) an affective component, comprising the negative emotional experiences of disorientation, lostness, and loneliness (see Peplau & Perlman, 1982; Rotenberg, 1994). The chapters in this book are guided by this conceptualization of loneliness, although they vary considerably in the emphasis placed on the two components.

Research supports the conclusion that a stable pattern of loneliness poses a serious threat to an individual's mental health and psychosocial functioning (see McWhirter, 1990).