The text engine allows queries to be formed from arbitrary Boolean expressions containing the keywords AND, OR, and NOT, and grouped with parentheses.

For example:

• information retrieval
  -  finds documents containing 'information' or 'retrieval'

• information or retrieval
  -  finds documents containing 'information' or 'retrieval'

• information and retrieval
  -  finds documents containing both 'information' and 'retrieval'

• information not retrieval
  -  finds documents containing 'information' but not 'retrieval'

• (information not retrieval) and WAIS
  -  finds documents containing 'WAIS', plus 'information' but not 'retrieval'

• web*
  -  finds documents containing words starting with 'web'