The document discusses different modes of documentary filmmaking that emerged in the 1920s, including poetic, expository, observational, participatory, reflexive, and performative modes. It provides examples for each mode, such as Leni Riefenstahl's Olympia (1938) for poetic mode, Night Mail (1936) for expository mode, films by Frederick Wiseman for observational mode, and Marlon Riggs' Tongues Untied (1989) for performative mode. The document also discusses theorists like Bill Nichols who identified these documentary styles and modes.