Start with a multi-disciplinary database:
Then move on to a subject-specific database:
Use subject headings to search more powerfully in the library catalog.
You can think of subject headings like "tags" that the library uses to identify works on a common topic. For example, one of the easiest way to find books of literary criticism about Miguel Cervantes is to do a subject search using the catalog's official subject heading:
Start your search with the name of the author and add words for criticism or interpretation. For example:
You can also search by country and century. For example:
Once you've found a book that's relevant to your topic, click on one of the Subject headings/Topics in the record (for example, "War in Literature") and it will take you to more relevant books.