Tertiary sources like Subject Encylcopedias and Dictionaries are an excellent path to follow when you wish to gain an overview of a historical period, geographical region, or more specialized toopic. Like Wikipedia-- but better because more trustworthy-- a Subject Encylcopedia or Subject 'Dictionary' offers a useful entry point to understanding your more narrow field of study by givinig an overview of the area, the "lay of the land" as we say.
Find below a list of useful tertiary sources.
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