Encyclopedias attempt to summarize the state of knowledge in a field of inquiry. A good encyclopedia can be a valuable starting point for your research.
Three online reference collections that students often find useful:
A very extensive collection of useful reference works published by Gale and affiliated publishers, including general and subject-specific encyclopedias. Gale is a major publisher of encyclopedias and other reference sources.
Large collection of encyclopedias and dictionaries. It includes some important reference works in History, Philosophy, Religious Studies, and related fields. Works tend to feature shorter entries, with exceptions.
Long articles organized around topics like Events (e.g. Estates General, De-Christianization, Vendee), Actors (e.g. Condorcet, Marat), Groups (e.g. Girondins, Sans-culottes), Institutions and Creations (e.g. Civil Code, Revolutionary Religion), Ideas (e.g. Equality, Public Spirit, Vandalism), and Historians (e.g. Burke, Fichte, Hegel). Includes color illustrations.
Includes a chronology, a dictionary of people, places, events, and concepts, and an extensive bibliography organized by sub-topics like "Religion and the Church", "Cultural Histories", "Social and Economic Histories", "Women and Gender", "International Reactions", and so forth. A more basic version of this work is the Companion to the French Revolution by John Paxton.
2 vols. English translation of Dictionnaire Européen des Lumières. "Focuses primarily on concepts, bringing to bear recent advances in scholarship and new geographic and disciplinary approaches [...] Shorter articles treat cultural institutions and categories ('Salons,' 'Conversation'). A third tier treats anthropological categories ('Body,' 'Love,' 'Work') [...] A general bibliography cites sources common to many articles, key research tools, and major journals in the field" (from the Choice review by S. F. Roberts).
4 vols. "Unlike Delon's volumes [above], which have a French and European orientation, Kors largely focuses on British and North American perspectives" (from the Choice review by W. Baker).
2 vols. Similar to the Historical Dictionary above, but the articles are lengthier, and include references for further reading. Also includes a fine index.
Online version of the 5 volume original. "Articles span social, political, economic, and intellectual history, but demonstrate most prominently the new influence of cultural studies" (from the Choice review by M. Todd).
Identifies biographical entries in hundreds of reference sources, many available only in print. Especially useful for locating biographical information on obscure individuals, or people not well represented in the major biographical reference works.
Biographies of men and women, deceased at least five years, who, in the judgment of the editorial board, made important contributions to British history and culture. Includes access to articles from the original, Victorian classic, The Dictionary of National Biography.
Standard reference work for American biography. This is the online version of the 24 volume original plus updates. Biographies of men and women, deceased at least five years, who made especially important contributions to American history and culture. Only includes deceased Americans deemed historically significant by editorial board.
Biographical dictionary of members of the French National Assembly. See also Dictionnaire des Conventionnels for members of the National Convention, 1792-1795.
Population, labor and industry, trade, and so forth. Few of the statistics here begin before 1800. Still, a good overview of the kind of statistical information available.
In addition to bibliographies, this guide includes chronology, short biographies, glossary, and a selection of source documents. Part of the series, Greenwood Guides to Historic Events, 1500-1900.