Natural Language Processing (NLP), hitherto a largely academic discipline, has found itself at the centre of an information revolution ushered in by the Internet age, as demand for human-computer communication and information access has exploded. Emerging applications in computer-assisted information production and dissemination, automated understanding of news, understanding of spoken language, and processing of foreign languages have given impetus to research that has resulted in a new generation of robust tools, systems, and commercial products. This volume focuses on the use of Natural Language Processing (NLP) in information retrieval, the technology that grew out of library research to become our best hope in dealing with today's information overload. The book gives a broad overview of the work being done at the junction of these two important fields, and suggests directions for future explorations. It is organized into two loosely structured parts. The first part, consisting of Chapters 1 through 7, discusses research systems and evaluations that represent major avenues where the impact of NLP technologies in information retrieval is being explored. The second part (Chapters 8 through 14) describes specific implementations and prototypes of information systems where NLP techniques are used or proposed to assist in accurate retrieval, text categorization, question answering, and in organizing the results for the user.