This work addresses fundamental problems in three facets of discourse processing, (1) the focus of attention of discourse participants, (2) the use and understanding of pronominal reference, and (3) the coherence of discourse. The research focuses on the interaction among these facets within a discourse segment. It will refine and expand current computational theories of discourse coherence and reference at this local level. The approach is interdisciplinary: it includes the development of algorithms that embody the theory and psychological investigations to determine constraints on parameters of the theory (e.g. the ordering of candidate referents for pronouns). It will empirically test the claims of the theory as a model of human language use, and will compare the performance of algorithms for handling pronouns employing the constraints of this theory with alternatives based on other theories. The results will contribute to computer science and the cognitive sciences in three major arenas: the construction of more fluent and robust natural-language processing systems; the development of more computationally sufficient psychological theories of discourse processing; and, potentially in the longer term, the design of more sophisticated computer languages (e.g. database-access languages, system-interface languages).