This is a marvelous collection. The papers have been selected with care, and provide an unprecedented concentration of knowledge about information retrieval. The introductory material, by two of the leading researchers in IR, is itself a valuable reference to the history and status of the field and the important ideas in it. This book will instantly become the most important reference in the field. --David D. Lewis, AT&T Labs Information retrieval systems provide end-user access to the huge range of textual information resources that are now available. The techniques used are now being applied to multimedia retrieval, and to related information-seeking tasks such as information extraction and summarization. This collection contains papers covering both general theory and specific method, to offer a comprehensive view of the entire field. Each section consists of a carefully selected group of papers, together with a critical introduction to that topic and an extensive list of additional references.