The Cambridge Histories Collection includes multi-volume works on many geographical units and historical themes, and can help you with the general narrative of a time period and major academic debates on the issues.
Looking for background information and overviews, but want something more reliable than Wikipedia?
All of the reference tools below--encyclopedias, dictionaries, bibliographies, and more--have been designed by expert scholars to provide overviews, as well as help researchers get their bearings on key scholarly literature in a given area of study.
Oxford Research Encyclopedias for History offer synopses of key historical topics and themes in different geographic regions. Each encyclopedia article includes overview information, a discussion of the scholarly literature, a list of key primary sources, links to digital resources, and suggestions for further reading.
These databases include encyclopedias and other reference works. Use them to find basic background information and overviews of countries, people, and major historical events:
