For shorter biographical articles or entries on a person, reference works are a good place to start. They'll often include brief bibliographies of additional sources, too.
Search in the library catalog on the person's name and the term "biography" or "autobiography." For example, searching
Zora Neale Hurston biography
in the library catalog will turn up both biographies about and autobiographies by the author.
Tip: sometimes you'll get better results if you run your search as a "Subject keywords" search.