Reference sources are invaluable for defining key concepts, providing brief overviews of a subject, and identifying major theories and research developments. They can provide you with the background you need to select and develop a topic of research, or help you explore internship or career opportunities.
Subject encyclopedias provide an overview of your topic, often including history, current state, policy issues & relevant theories, while specialized dictionaries provide definitions of terms or phrases unique to the field.
Another great source for overviews of social issues: