In "A Film Unfinished," Yael Hersonski turns something evil into a work of education and remembrance. The Israeli director takes an uncompleted Nazi propaganda film shot in the Warsaw Ghetto during World War II and shows how the original filmmakers staged scenes intended to serve their anti-Semitic propaganda purposes. Yet these German filmmakers, whose identities remain lost in time, also provided later generations with rare views of Nazi oppression and barbarism.

"A Film Unfinished," which generated considerable critical acclaim when it was released in movie theaters last year, as well as controversy over its "R" rating, comes out on DVD this week (Oscilloscope Laboratories, $29.99, rated R). It is a painful film to watch, but an important one.

The basis for "A Film Unfinished" was the discovery in 1954 of a single movie reel entitled "Das Ghetto" ("The Ghetto"). Inside was an unfinished one-hour Nazi-made film about the Warsaw Ghetto, a film without titles, credits or narration. The footage was shot in May 1942, just a few months before a majority of the 450,000 Jewish inhabitants forced to live in an area less than three square miles were deported to the Treblinka death camp....