Sometimes, a secondary source (a source that analyzes primary sources to understand why a phenomenon happened, such as scholarly articles published in academic journals, research books, biographies, textbooks, etc.) can be treated as a primary source depending on the context of your research. For example, if you are doing a research study about how biology teaching has changed through time, then biology textbooks are considered a primary source.
Caption: One of 634 drawings from the collection, "They still draw pictures", which is part of the Southworth Spanish Civil War Collection housed in the Mandeville Special Collections Library at UC San Diego.
Explore these resources following the links below:
Note: As any primary source used for historical research, be aware of the strengths (first witness accounts) and weakness (bias, forgetfulness, sensationalism) of this type of source.