Primary and Secondary Sources: A Working Definition
Launch library · evergreen read
A primary source is created at or near the time of the event it describes, by someone with direct knowledge of it: a letter, a ledger entry, a photograph taken on the day. A secondary source interprets or synthesises that material after the fact, often from a considerable distance in time.
The distinction matters because each carries different strengths and different weaknesses. Primary sources offer immediacy but can be narrow or shaped by a single vantage point, while secondary sources offer context and comparison but add another layer between the reader and the original underlying evidence.
Strong evidence craft uses both deliberately and knowingly: primary material to anchor specific claims, secondary material to situate them properly, and a clear sense in the writer's own mind of which source is doing which job at any given moment in the piece. Losing track of that distinction, even briefly, is one of the more common ways a promising piece of writing quietly loses its footing.