The third step is to establish relationships between the concepts/keywords which best express your topic. Boolean operators (AND, OR, NOT) allow you to form compound searches by combining two or more terms together. Parentheses also allow you to group terms together.
AND narrows a search by finding records that must contain all the terms you have entered. Using AND lets you be more precise by adding additional required concepts.
OR broadens a search by finding records that contain either or all of the terms you have entered. Using OR makes your search wider by searching for similar or related terms.
NOT narrows a search by finding records that contain one term but not another. Using NOT lets you be more precise by excluding certain terms. For example, if you're researching Apple computers, you might search for "apple NOT fruit", so that your results won't include items about apples as food.
Parentheses forms compound searches by giving you the ability to group similar or related terms together.
Quotation Marks are used if you are searching for an exact phrase. By using quotation marks, your results will return only items that include those exact terms in that exact order.
Your list might now look something like the following:
Concept 1 and 2
(Antony OR Cleopatra)
(Shakespeare OR Shakespearean)
(power OR politics OR politician OR political OR rome OR roman)