In order to make further progress in the field of automatic text retrieval, approaches extending current standard full text indexing methods need to be investigated. This book advocates keyword indexing as one such feasible approach. More specifically it discusses the development of an algorithm for automatic keyword extraction and presents a number of experiments in which the performance of the algorithm is incrementally improved. Automatic keyword extraction is the task of automatically selecting a small set of terms describing the content of a single document. That a keyword is extracted...