Primary sources are the "materials on a topic upon which subsequent interpretations or studies are based, anything from first-hand documents such as poems, letters, diaries, court records, and interviews to research results generated by experiments, surveys, ethnographies, and so on."*
Primary sources are records of events as they are first described, without any interpretation or commentary. They are also sets of data, such as census statistics, which have been tabulated, but not interpreted.
Primary sources were either created during the time period being studied or were created at a later date by a participant in the events being studied (as in the case of memoirs). They reflect the individual viewpoint of a participant or observer. Primary sources enable the researcher to get as close as possible to what actually happened during an historical event or time period.
Examples of primary sources:
Autobiographies and memoirs
Diaries, personal letters, and correspondence
Interviews, surveys, and fieldwork
Internet communications on email, blogs, listservs, and newsgroups
Works of art and literature (Novels, Paintings)
Photographs, drawings, and posters
Books, magazine and newspaper articles and ads published at the time
Public opinion polls
Speeches and oral histories
Original documents (birth certificates, property deeds, trial transcripts)
Research data, such as census statistics
Official and unofficial records of organizations and government agencies
Artifacts of all kinds, such as tools, coins, clothing, furniture, etc.
Audio recordings, DVDs, and video recordings
Government documents (reports, bills, proclamations, hearings, etc.)
Scientific journal articles reporting experimental research results
Secondary sources, on the other hand, offer an analysis or a restatement of primary sources. They often attempt to describe or explain primary sources. Some secondary sources not only analyze primary sources, but use them to argue a contention or to persuade the reader to hold a certain opinion.
Examples of secondary sources:
Reference books, including dictionaries, encyclopedias, and atlases
Articles from magazines, journals, and newspapers after the event
Literature reviews and review articles (e.g., movie reviews, book reviews)
History books and other popular or scholarly books