ABSTRACT Emotional well-being, which includes life satisfaction, life purpose, and positive emotions, is a key public health target. Although health can influence well-being, only recently has there been increasing attention on how overall well-being can influence health outcomes. Critical knowledge gaps exist in both understanding the research on the role of emotional well-being in health and in measuring well-being outcomes, which constrain valid and rigorous evaluation of intervention strategies. The interdependence of health and well-being within and among family members has not been well-characterized: the health and well-being of a patient affects family members, but the well-being of family members--especially informal caregivers or parents--can also directly affect the well-being of the patient. Moreover, these interrelated effects vary across the lifespan, from child well-being within a family to elder well-being among family members and relatives. The specific aims of this U24 research network proposal focus on developing a coordinated set of collaborative, transdisciplinary mechanisms designed to create, launch, and sustain a new generation of well- being researchers and innovative research activities across the lifespan, with a special emphasis on measuring family well-being and child quality of life: (1) improve access to and use of emotional well-being measures by creating a web-based resource repository of curated instruments, research findings, datasets, and training/learning materials; (2) stimulate well-being research through funded pilot projects that address the measurement of well-being across the lifespan with dedicated funding for pediatric quality of life projects; (3) assemble a research scholars corps with multidisciplinary training and expertise that will support and foster a pipeline of scholars for future research on measurement. This set of activities will serve to coalesce this emerging field, building research capacity to support better evaluation of interventions and improving public health through the measurement of measurement of well-being at the population level.