Longitudinal inquiry has long been recognized as a uniquely powerful method for seeking understanding of psychological development. A 30-year longitudinal venture is described--its theoretical motivation, methodological rationale, and details of implementation. Some of the novel and implicative findings the study has generated are briefly described. Common to all of the results is an absolute reliance on long-term, widely ranging, independent data. Although specific aspects of the study have appeared over the years, its intentions and scope are recounted only here. By and large, the organizing constructs of ego-control and ego-resiliency find impressive support in various empirical inquiries, here quickly described. Methodologically, a number of savvy research procedures useful and perhaps even necessary in longitudinal research are conveyed. The troublesome burdens but ever-alluring attractions of longitudinal inquiry are noted. A forthcoming Web site will contain the extensive 30-year longitudinal data bank together with explanatory information. Psychological investigators may find these imminently available data resources useful.