Searching which uses a few keywords, or important words, to retrieve books or articles on a specific topic or associated with those words in some way. The keywords could be used to search from the text of the document (if it is a full-text database), or some named Field (author, title, etc. ) depending on the Database being used and the searcher's intent. Often useful for very new topics for which controlled vocabulary indexes will not have a subject term yet established. Searching by keyword often utilises boolean searching.