Book excerpt: Published in 1992, like the first, this second edition is not intended as introductory textbook command-driven, Boolean searching. It is targeted at online searchers who already have some knowledge of command languages and may be proficient searchers on databases in one or two subject areas, but when required to venture into new and less familiar territory still need guidance. It is also offered to end users who possess the subject expertise but lack of information retrieval know-how. The Manual is offered as a guide to database selection and a navigational aid through the twists and turns of the retrieval maze; at least some of the dead ends and backtracking may thereby be avoided. This volume, written by experts in their various fields, deals with the subject coverage and record structures of specific databases, offers comparisons between databases (context, indexing procedures, updating policies, etc.), discusses the choice between online and CD-ROM sources (and between hosts if online is selected), and illustrates strategies with numerous search extracts.