Books are organized via categories developed by the Library of Congress. Most academic libraries at U.S. colleges and universities now use the Library of Congress system. Some subject headings reflect older modes of thinking and can be objectionable in contemporary usage (see case study note in the middle column). Subject headings are extremely useful, however, for identifying all books that share the same subject heading.
You can copy and paste the following subject headings into Primo.
Case study: In the spring of 2016, the Library of Congress announced that it would be replacing the subject heading "illegal aliens" with the terms "noncitizens" or "unauthorized immigration." Republican members of a House Appropriations Subcommittee objected. A House vote in June 2016 reinstated the use of "illegal aliens" as a subject term. Currently, "illegal aliens" remains a Library of Congress Subject Heading. Many catalogers are using the terms proposed in 2016 by using the option of "additional subjects." These additional subjects are not hyperlinked because they are not Library of Congress Subject Headings, but they can be found through keyword searches. Here's an example via the catalog record for the recently published study by Beth Lew-Williams, The Chinese Must Go.
Prof. Gomez highlights the scholarly journals listed below as being especially relevant to your research.