Diary Of The Dead is the latest in George A Romero's zombie series. (The previous films are: Night Of The Living Dead, Dawn Of The Dead, Day Of The Dead, and Land Of The Dead. The first two are notable for their social commentaries and for their then-unprecedented levels of on-screen gore.)
Like Cannibal Holocaust and The Blair Witch Project, Diary Of The Dead is a 'mockumentary' comprised of purportedly recovered footage. As in those two earlier films, we are first introduced to the filmmakers and their equipment (taking care to establish the multiple cameras, thus enabling the real filmmaker to justify shot/reverse-shot editing). The same themes - that filming an event makes it more real, and that the camera viewfinder filters reality - are explored in all three films.
Diary Of The Dead's film-within-the-film is titled The Death Of Death. The film's real title, and Romero's name, do not appear until the end credits, though Romero does have a cameo role as a police officer (and there are also cameos by Quentino Tarantino and Wes Craven, as radio reporters).