This paper describes a system for the computer understanding of English. The system answers questions, executes commands, and accepts information in normal English dialogue. It uses semantic information and context to understand discourse and to disambiguate sentences. It combines a complete syntactic analysis of each sentence with a heuristic understander which uses different kinds of information about a sentence, other parts of the discourse, and general information about the world in deciding what the sentence means. The objectives of the project are a practical language-understanding system, a better understanding of what language is and how it is put together, and an understanding of what intelligence is and how it can be put into a computer. (Author/VM)