BOOLEAN LOGIC

Boolean logic is the bedrock of searching. It uses AND, OR, and NOT to tie concepts together when you search in databases, indexes, or the Web. When used in this way, AND, OR, and NOT are called Boolean Operators. They can broaden or narrow your search.

Move your mouse over the AND, OR, or NOT below to see how Boolean Logic works, or see a static chart:

TERM	STATEMENT	WHAT IT DOES	EXAMPLES (shaded areas indicate retrieval)
AND	cats AND dogs	searches for documents that discuss both cats and dogs
OR	cats OR dogs	searches for documents that discuss either cats or dogs
NOT	cats NOT dogs	searches for documents that discuss cats but not dogs

Helpful explanations of Boolean Logic:

• Online Study Guide: Boolean Logic (Ithaca College Library)
• A Primer on Boolean Logic (American Psychological Association)
• More on Boolean Logic from Duke University Libraries
• Really Advanced Boolean Logic with diagrams from Colorado State University Libraries

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