An information retrieval system is designed to analyse, process and store sources of information and retrieve those that match a particular user's requirements. A bewildering range of techniques is now available to the information professional attempting to achieve this goal. It is recognized that today's information professionals need to concentrate their efforts on learning the techniques of computerized information retrieval. However, it is this book's contention that it also benefits them to learn the theory, techniques and tools that constitute the traditional approaches to the organization and processing of information. In fact much of this knowledge may still be applicable in the storage and retrieval of electronic information in digital library environments. This fully revised second edition has been thoroughly updated to incorporate major changes in this rapidly expanding field since the first edition in 1999, including multimedia information retrieval, user interfaces and digital libraries.