A biography is a written account of a person's life. It a reference source, or a resource that gives you basic background information in order to inform your further research. Use biographies to help you understand the period in which a person lived, their personal stories, and to help you generate search terms.
American National Biography is useful for research in American history because it contains the biographical information, including overviews of their contributions, of over 18,700 people who shaped American history. It is a one-stop shop for basic biographic information on Americans of the past.
Use this brief tutorial to introduce yourself to American National Biography. Watch it here on Youtube for higher resolution.