The back matter of a report refers to the material found at the end of a document containing supplementary information that is complementary to the main report. This information typically includes such items as appendices, endnotes, bibliographies, and additional sources of data. The back matter is sometimes referred to as back-of-the-book material, and it helps readers to gain more in-depth knowledge on a specific topic or set of topics that are covered in a given report. Back matter can provide supplementary information in various formats, such as data sets, tables, diagrams and graphics, as well as citations and recommendations for further reading, thus providing readers with information beyond what is written in the main body of the report. Depending on the specific topic and purpose of the report, the back matter may cover both the factual and interpretive elements of the research.