This volume provides unique and valuable firsthand accounts of the most important longitudinal studies of attachment. Presented are a range of research programs that have broadened our understanding of early close relationships and their role in individual adaptation throughout life. In addition to discussing the findings that emerged from each study, leading investigators offer rare reflections on the process of scientific discovery. Themes addressed include the complexities of designing studies that span years or even decades; challenges in translating theoretical constructs into age-appropriate assessments; how Bowlby's original models have been refined and expanded; and how attachment interacts with other key influences on development.