This document discusses the purpose and types of documentaries. It begins by explaining that documentaries aim to document facts using footage, interviews, reconstructions, and observations. A documentary relies on eyewitness accounts and uses narration to guide the audience. There are many documentary styles including fully narrated, fly on the wall, mixed, self-reflexive, docu-drama, and docu-soap. The document also discusses influential documentary theorists John Corner and John Grierson, including their definitions and contributions to the genre.