This paper provides an overview of an ongoing research program on natural language communications, indicating its status as of June 1978, and its short term goals. This research seeks to identify and computationally formalize the knowledge and processes needed for participation in natural language dialogs about ongoing tasks. The paper describes (1) the knowledge embodied in an existing system that interprets utterances in such dialogs, (2) the formalisms developed for encoding this knowledge, and (3) the framework in which the knowledge is combined and coordinated during the interpretation process. The paper also indicates anticipated extensions that will lead to refinements of interpretations. These extensions include the concept of modality, the use of the focus and goals of the dialog in the identification of the referents of pronouns, and the use of knowledge about the goals of the other dialog participants in the interpretation of utterances.