Primary sources are materials produced by people or groups directly involved in the event or topic under consideration, either as participants or witnesses. Examples of primary sources include eyewitness accounts, letters, diaries, newspaper and magazine articles, speeches, autobiographies, treatises, census data, and marriage, birth, and death registers.Secondary sources are books and articles in scholarly journals that comment on an interpret primary sources. Source: Mary Lynn Rampolla. A Pocket Guide to Writing in History, 4th ed. (Boston: Bedford/St. Martin's), 5-6.
When you are conducting a search, you can include your topic plus keywords such as diary, oral history, or letters. For example, keywords : borderlands AND Russia AND diary would lead you to a book "Everyday Jewish Life in Imperial Russia : Select Documents, 1772 - 1914". Our catalog would also lead you to Jews--Russia--Social life and customs--History--Sources to investigate related resources.
Use the term "Finding Aid" to locate digitized materials. As collections worldwide are digitized, most collects have a finding aid to help you navigate a collection's contents. If you use "Finding Aid" and "WWII Letters", you may find excellent primary sources.