THROUGHOUT HIS CAREER, Errol Morris has been making documentaries about death; from the death of beloved animals (Gates of Heaven) to a man on death row (The Thin Blue Line), from the death of mankind (Fast, Cheap and Out of Control) to the death of the universe (A Brief History of Time). This time around, he approaches the subject by studying a man who thinks he has cheated death by becoming death.

Let me elaborate: The documentary is about Fred A. Leuchter, Jr., an odd-looking chap who is "a self-styled execution technologist" -- meaning he repairs and improves the death machines used by our prison system. He started his career by first repairing electric chairs; years passed, and he extended his repertoire to gas chambers, lethal injection mechanisms, and even the gallows.

Once he starts to gain national attention for what he does, Leuchter starts to believe he is doing humanity a big favor by improving these death machines and taking the bite (or sting) out of death. Questions of guilt or innocence, the fact that most of the men killed by his "humane" inventions are disproportionately black, or any other social issue that would worry a normal human being never cross his mind. His world is sealed. When it's time to die, it is time to die. He doesn't care about the philosophical implications of killing, or our innate dread of nonexistence -- only how he can make your plunge into the eternal abyss as painless as possible. This is his great folly, and what makes him an agent of evil. Any human who wants to assume the role of death, to adopt its stark qualities, ultimately becomes the very embodiment of evil: Mr. Death.

After establishing himself as the number-one death expert in America, he was asked by a Toronto neo-Nazi (Ernst ZĂĽndel) to prove or disprove the known truth that hundreds of thousands of Jews were gassed at Auschwitz. It is a fool's task, a project only a man bloated by the pride (or delusion) of having defeated death would even think to undertake. Once confronted with evil at this scale, Leuchter finally reaches the limits of his illusion. It is now time to fall, and Errol Morris makes sure he falls hard; harder than poor, prideful Icarus fell when he flew too close to the sun.

When I spoke to Errol Morris on a terrible conference call with a critic from an online film site, he said something that caught me by surprise. He agreed that Mr. Death was about a man who was foolish enough to believe he had defeated death -- indeed, that he was even stronger than death and the Nazis put together -- but he also said this was his Holocaust film.

"I have always wanted to make a Holocaust film, but not the standard Holocaust film," he said in a thoughtful, mischievous, even pompous voice (he was in his office in Cambridge, Massachusetts, and it was snowing outside his window). "As a filmmaker and as a Jew, the film is an attempt to ask questions about what I consider to be the mystery of the Holocaust -- the mystery of how it could have happened, how people could have done this -- and in some small way I think Fred brings us into that mystery. Fred is a vehicle into those questions about evil and self-deception... now, if you contrast this particular movie with, say, Schindler's List -- Schindler's List says anyone can be a hero, and anyone can be a villain. This film has a more frightening idea. Anybody can think they are hero. That is Fred's story."

This disclosure surprised me. I had thought the Holocaust part of the film was arrived at by pure accident; that Morris' first impulse was toward a simple joke about a man who repairs death machines, and later he stumbled on the serious story of the Holocaust. Whatever designs he initially had in mind, in the end Errol Morris manages to get even closer to the center of his primary concerns -- death, the nature of evil, self-deception. This is why Mr. Death stands out as one of his best films.