Primary sources provide a firsthand account from a particular time period. These are original documents written by people who witnessed an event or lived in the same time. Good examples of primary resources include letters, diaries, court records, photographs, and interviews.
Secondary sources, on the other hand, offer an analysis of primary sources. Some secondary sources not only analyze primary sources but use them to argue a point or to persuade the reader to hold a certain opinion. Examples of secondary sources include dictionaries, encyclopedias, books, and journal articles.
For example, David McCullough’s biography, John Adams, is an example of a secondary source that explores the life of John Adams through the use of primary sources, including letters, diaries, contemporary newspaper articles, and other sources from the time period.