Primary Sources vs Secondary Sources vs Tertiary Sources
Primary sources are documents, objects, images etc, that come directly from that particular time period and are created by people from that era.You will often need to look to other sources to develop more context and background information. (not just written) Ex. letters, autobiographies, speeches, receipts, etc.
Secondary sources are analyzed and edited information found primarily from primary sources and other secondary sources. Usually written after the event/time period. This will often be the bulk of your research. Ex. books about a topic, scholarly articles, etc.
Tertiary sources synthesize the information that is found in both primary and secondary source material. They are often the first place to go when you start research to give you context but are not appropriate for citation or for use in your papers or presentations. Ex. Textbooks, encyclopedias, reference materials.