This will be the third edition of the highly successful "Text Information Retrieval Systems." The book's purpose is to teach people who will be searching or designing text retrieval systems how the systems work. For designers, it covers problems they will face and reviews currently available solutions to provide a basis for more advanced study. For the searcher its purpose is to describe why such systems work as they do. The book is primarily about computer-based retrieval systems, but the principles apply to nonmechanized ones as well. The book covers the nature of information, how it is...