Boolean operators include AND, OR, and NOT (ANDNOT or AND NOT). Boolean operators tell the search engine which terms you want to include or exclude from your search results. By default most search engines will perform an AND search regardless of whether or not you use the AND operator. Most search engines and online databases recognize Boolean operators. If you visit a search engine and are unsure as to what operators it recognizes be sure to visit that engine's help files. Remember, every search engine works differently; do not assume that all search engines recognize all Boolean operators. The following pages describe each Boolean operator in detail and provide examples of which search engines accept which operators.