Researching a specific designer, design style or movement (for example, Art Deco or Modernism)? Looking for basic background information on a time period in history? Reference sources can give you a brief overview of your topic, suggest keywords to search when you get to the catalog or article databases, and some entries may also include a bibliography of additional sources to consult for more information.
Want to find out more about the time period in which a designer lived or during which a design style or movement emerged? History reference works are a good place to start. (Note: when it comes to finding out about a designer's influences and legacy, you'll probably discover this information in biographical or analytical articles or books.)