What is a primary source in this topic?

The answer

A primary source is material created at the time being studied, such as a ship's log, law, advertisement, letter or narrative by an enslaved person. Each reflects the viewpoint and purpose of its creator, so it must be read critically. Most records of the trade were made by traders and officials, who described people as cargo, so students should always ask who made the source, why, and whose voice is missing.