Before conducting in-depth research, it is important to gather information you have about your topic and consider what you still need to know. This can include dates, places, terminology, and names of persons/entities involved in events or phenomenon you’re studying. Reference tools like dictionaries, encyclopedias, and handbooks are useful for this preliminary research phase.
Dictionary of American History by 
The Oxford companion to United States history by 
The Oxford encyclopedia of American business, labor, and economic history by 
The Civil Rights Movement by 
