I know this isn't specifically on genealogy, but it may help with your research R Boolean Basics "Boolean Operators," explains University of Albany--State University of New York University Libraries, "are used to connect and define the relationship between your search terms. When searching electronic databases, you can use Boolean operators to either narrow or broaden your record sets." They note that "the three Boolean operators are AND, OR, and NOT" and provide this simple illustration for using each: AND [+] Use AND to narrow your search: all of your search terms will present in the retrieved records. / Example: Online courses AND academic performance boolean searching/ OR Use OR to broaden your search by connecting two or more synonyms. /Example: online courses OR Web-based instruction OR distance education The database retrieves all the unique records containing one term, the other, or both. / NOT Use NOT to exclude term(s) from your search results. / Example: higher education NOT community colleges /