Part I. Introduction: 1. Childhood and adolescent loneliness: an introduction Ken J. Rotenberg; Part II. Theoretical and Assessment Issues: 2. The conceptualization and measurement of childhood loneliness Beverley Terrell-Deutsch; 3. Understanding the origins of childhood loneliness: contributions of attachment theory Jude Cassidy and Lisa J. Berlin; 4. Developmental change in the sources of loneliness in childhood and adolescence: constructing a theoretical model Jennifer T. Parkhurst and Andrea Hopmeyer; 5. Loneliness through the eyes of children Shelley Hymel, Donato Tarulli, Laura Hayden Thomson and Beverley Terrell-Deutsch; Part III. Loneliness in Childhood: 6. Loneliness during early childhood: the role of interpersonal behaviors and relationships Kim B. Burgess, Gary W. Ladd, Becky J. Kochenderfer, Sharon F. Lambert and Sondra H. Birch; 7. Antecedents of loneliness and the ability to be alone in young children Lisa M. Youngblade, Lisa J. Berlin and Jay Belsky; 8. A social information-processing approach to children's loneliness Nicki R. Crick, Jennifer K. Groptpeter and Carol M. Rockhill; 9. Parental antecedents of children's loneliness Ken J. Rotenberg; 10. The friendship experience in middle childhood and adolescence: implication for understanding loneliness Jeffrey G. Parker, Jill L. Saxon, Steven R. Asher and Donna M. Kovacs; Part IV. Loneliness in Adolescence: 11. Adolescent loneliness, self-reflection and identity: from individual differences to developmental processes Luc Goossens and Alfons Marcoen; 12. On the uses of loneliness in adolescence, Reed W. Larson; 13. Social self-discrepancy theory and loneliness during childhood and adolescence Janis B. Kupermidt, Kathy B. Sigda, Mary Ellen Voegler and Constantine Sedikides; 14. Self, other and loneliness from a developmental perspective Lorrie K. Sippola and William M. Bukowski; 15. Adolescent loneliness and maladjustment: a focus on gender differences Linda Loenig and Robin Abrams; Part V. Prospective: 16. Examination of loneliness across the life cycle: two solitudes or unified enterprise? Daniel Perlman and Monica Landolt.