When the narrator/director of the film begins with praising a neighborhood peeping tom for "getting away with it" you can pretty much guess what this is all about. Ostensibly an attempt to uncover the world of proto-snuff and other depraved 'underground film making', it becomes a numbing vehicle for it- tarting itself up with intellectual deconstructions and interviews with the participants of these movies and and ultimately revealing itself as another sad exercise of the... form.
Bitter, sociopathic white males acting out their inner rage by staging graphically detailed depictions of the murder of one woman after another may be a lot of things, but one thing it will never be is *art*. Gaspar Noe's movies are better-produced versions of the same thing, and just as unworthy of your time. Proceed accordingly.
2 Stars for genre fans' ability to harvest anecdotes/background information on these movies and that's about it.