Love and loneliness hold special interest at a time when divorce and geographical mobility pull so many people apart. Attachment theory offers a useful integrative framework to study adolescent and adult love and loneliness. Attachment theory has three propositions: (1) when an individual is confident an attachment figure will be available when he desires, the person will be less prone to fear; (2) confidence in availability of attachment figures is built up over the years of immaturity; and (3) varied expectations of responsiveness of attachment figures that individuals develop during years of immaturity are basically accurate reflections of their experiences. The continuity of attachment style across the lifespan is probably maintained in a number of interrelated ways including emotional, cognitive, and behavioral ways. The organization of a child's attachment behavior tends to persist across the lifespan. Early attachment behavior and later romantic love share similarities. Differences exist between anxious/ambivalent lovers and secure lovers. Transient loneliness is a natural component of attachment-system activations. Three kinds of people emerge from attachment studies: those relatively secure who have enjoyed reasonable parenting, those who are anxious/ambivalent in close relationships and low in ego-resilience, and those avoidant in close relationships who were rebuffed in early secure attachment efforts. An attachment approach to love and loneliness holds promise for both theory and research. References and figures are appended. (ABL)