Funds are requested for a longitudinal followup of 79 couples of whom were distressed and 29 of whom were happily married. Evidence from our first physiological study of the role of emotion in marriage has led to the development of a biologically-based theory of distressed marital interaction and how marital relationships change over time. We have been able to obtain a high degree of predictability with this parsimonious theory. We suggest that the degree of sympathetic nervous system (SNS) arousal in 1983 will predict health and changes in relationship satisfaction in 1986; that the behaviors used in 1983 to reduce SNS arousal in 1983 will predict changes in behavior patterns over three years; that the nature of symbolic conflict will relate to changes in relationship satisfaction; and that there will be a general pattern of sex differences in SNS arousal that will relate in specific ways to sex differences in interaction. We also propose the test of a taxonomy of marital interaction that has seven types of marriages, three types of noncompanionate and four types of compationate couples. The unique contributions of the multimethod data base and theory we are constructing are discussed in the proposal.