Q. What is Boolean searching?

In Boolean searching, the operators AND, OR and NOT to narrow or broaden a search by telling your search tool how your search terms are related to each other. You do not have to enter them in capitals. The Venn diagrams below help to visualize the meaning of AND, OR and NOT. The colored area indicates what will be included in your results.

AND

• The operator AND narrows the search by making sure you only get results with both search terms.
• AND decreases the number of results but makes sure that all relevant concepts are included in every result.
• In University Libraries' catalog as well as many library databases and search engines, if you enter search terms without an operator, the search will behave like an AND was between them.

Examples:

• gambling AND addiction
• gravity AND relativity
• education AND race AND outcomes

You want to find books that are about both moths and butterflies, not just one or the other. 

OR

• The operator OR broadens the search to include results containing either search term or both. 
• OR expands the number of results and is particularly useful when there are synonyms for a concept or variant spellings of a word that you want to ensure are included.

Examples:

• medieval OR "middle ages"
• vergil OR virgil
• adolescent OR teenager OR teen

You want to find books that are about moths, books that are about butterflies, and books that discuss both. OR means more. 

NOT

• Combining search terms with the NOT operator narrows the search by not including any result with the search term after the NOT.
• NOT decreases the number of results but makes sure no results with irrelevant concepts are included. 

Examples:

• Phoenix NOT Arizona
• Tesla NOT automotive

You want to find books that are about moths but exclude anything with butterflies, even if they also include moths.