He is the author of the book Literature and Cognition, and was also editor of the book Formal Theories of the Commonsense World. He led SRI's text-understanding research, and directed the development of the abduction-based TACITUS system for text understanding, and the FASTUS system for rapid extraction of information from text based on finite-state automata.
He has written numerous papers in the areas of parsing, syntax, semantic interpretation, information extraction, knowledge representation, encoding commonsense knowledge, discourse analysis, the structure of conversation, and the Semantic Web.