Boolean operators allow you to combine your keywords to create a search that the databases can use to retrieve the results you need. The words AND, OR are the most commonly used Boolean operators. The third is NOT, which can be difficult to use because it might exclude useful results.
AND combines your search terms and looks for them together in search result. Example: A search for Leonardo da Vinci AND Michelangelo will retrieve records that have both keywords: Leonardo da Vinci and Michelangelo.
OR separates your search terms, finding records that contain either keyword. Example: A search for Leonardo da Vinci OR Michelangelo will retrieve records all the records that contain either of the search terms as well as records with both of the search terms.
NOT finds records that only have the first keyword, but will exclude records that have both keywords or just the second keyword. A search for Leonardo da Vinci NOT Michelangelo will find records only containing Leonardo da Vinci and will exclude records that also include Michelangelo or are only about him. This boolean operator is only useful when you want to exclude a topic that is often associated with your first keyword. For example, if you wanted articles about Leonardo da Vinci's paintings excluding the Mona Lisa, the search: Leonardo da Vinci NOT Mona Lisa. Just remember that this type of search is very narrow and might exclude records that also include information on your topic.
Samples of searches for art books in the library's online catalog