This is a competitive renewal application for a Research Scientist Award. Longitudinal research is described by 2 themes: l) How marriages change, which will involve modeling pathways to marital dissolution and to illness and immunosuppression; and 2) the transfer of marital discord to children, which will involve the mathematical modeling of triadic interaction (mother-father-baby), the prediction of the quality of parenting from newlywed marital interaction, and the prediction of child emotion regulation abilities and child outcome. The parents' "meta- emotion" structure is posited as the major intervening variable in marital processes, parent-child processes, and child outcomes. Children's cognitive and emotional development will be studied as they develop. At Time-1 the marriages of 120 newlywed couples were studied using a multimethod approach that collected physiological data synchronized with behavioral coding of interaction and a continuous self- report measure of perceived affect; interview and questionnaire data were also collected. Based on observational coding and questionnaire data, 50 of these couples were identified along a continuum of risk for marital dissolution (based on previous research) and these 50 couples participated in a 24-hour stay in an apartment laboratory in which autonomic, endocrine and immunological data were obtained as well as continuous recording of the marital interaction. All 120 couples are being followed through the transition to parenthood, which includes marital and other assessments during the pregnancy period and marital and parent-child interaction (and physiology) when the baby is 3 months old, following the Fivaz procedure. Children will be followed as they develop (as in previous studies by the candidate) in which child outcomes include peer social competence, behavior problems (as seen by parents and teacher), child academic achievement (controlling IQ), and health.