A secondary source analyzes, interprets, or summarizes information from primary sources.
Secondary sources include: texts about broad historical periods, works that focus on specific events or topics, literary and cultural criticisms, and works on theory and methodology. These materials can be books, book chapters, journal articles, and internet resources. Where a tertiary sources give basic information on a subject, secondary sources are analytical and interpretive.
The papers you write as History students will be secondary sources!