Boolean Search

Boolean searches use operators to perform more specific queries. Using "AND", "OR", and "NOT" (Boolean operators) allows you to refine the search by adding or removing specific terms. The "tilde symbol" (~), can be used in place of "NOT".

You can turn Boolean searching on or off using the radio buttons next to "Boolean Search:" on the Advanced Search page.

Examples of Boolean Searching:

  1. Query: I am looking for books about war.
    Boolean logic: OR
    Keyword search: war or military
  2. Query: I am looking for a book about cats and painting.
    Boolean logic: AND
    Keyword search: cats and painting
  3. Query: I'm looking for books by the author King, but not Stephen King.
    Boolean logic: NOT
    Author search: King not Stephen
  4. Query: I want to search for the book "To Have and Have Not" and "The Old Man and the Sea" by Ernest Hemingway.
    Boolean logic: OR
    Author search: Ernest Hemingway
    Title search: "To Have and Have Not" OR "The Old Man and the Sea"

    Note: In this example, there are Boolean operators within the titles of the books. You want the search to look for book titles, rather than use the words "and" and "not" as Boolean operators. To tell the search that you are looking for titles, it is necessary to use quotation marks (" ") around terms that you do not want considered as Boolean operators.
  5. Query: I want to search for volumes of "Harry Potter" published by different publishers.
    Boolean logic: OR, AND
    Keyword search: (Scholastic and Harry Potter) or (Bloomsbury and Harry Potter)

    Note: To group series of words together, use parentheses ( ). As in mathematics, use of parentheses will keep search terms together allowing the search to properly categorize and display results for you

Operator precedence

The Boolean operator "NOT" is given the highest precedence, followed by "AND", and then "OR". If you have two Boolean operators in one search, the search will run using the order of precedence. For example: You are searching for a book by Stephen King. You don’t want the book "IT", but do want books by Penguin publishers. The search results you see will display any books that match your criterion.

Parentheses can be used to force the order of processing. For example:

Keyword search: (Bloomsbury or Scholastic) and Harry Potter

If we alter the search above by surrounding the OR words with parentheses, the search engine will process the two related terms first. Next, the search engine will combine this result with the last part of the search. Using this method, the related OR terms are kept together as a logical unit.

Invalid Boolean Searches

The following Boolean searches are invalid and will not be completed because the search expression is incomplete: