Les Blank's "Burden of Dreams" is remarkable. "Fitzcarraldo" involved torturous, dangerous on-location scenes, and documentarian Les Blank is himself brilliant and unafraid to ask hard questions, or to show us Herzog, flaws and all. The making "Fitzcarraldo" is the stuff of legend. The movie was shot on location deep in a South America rain forest, a thousand miles from civilization. When the first version of the film was halfway made, its star, Jason Robards, rushed back to New York with dysentery and his doctors forbade him to return to the location.

Herzog replaced Robards with Klaus Kinski (star of his "Aguirre, the Wrath of God"), but meanwhile, co-star Mick Jagger left the production for a concert tour. Then the second version of the film got caught in a border war between tribes of Indians. The whole production moved twelve hundred miles to a new location; there, plane crashes, disease, and attacks by unfriendly Indians added to the incredible task Herzog set himself: to show his obsessed hero using teams of Indians to pull an entire steamship up a hillside using only block and tackle.

Blank and associate Maureen Gosling visited both locations; the documentary includes the only available record of some of the earlier scenes with Robards and Jagger, and scenes in which Herzog seems to be going mad, blaming the evil jungle and the depth of his own compulsions. In "Fitzcarraldo," you can see the incredible strain as men try to pull a steamship up a sharp incline, using only muscle power and a few elementary mechanics. In "Burden of Dreams," Blank's camera moves back one more step, to show the actual mechanisms by which Herzog hoped to move his ship. A giant bulldozer augments the block-and-pulley, but is barely equal to the task. The Brazilian engineer in charge walks off, warning that lives will be lost.

What drives Herzog to make films that test his sanity and risk his life? For Herzog, that IS the purpose of film. Each of his is in some way a challenge hurled at the odds. Herzog has made films on the slopes of active volcanoes, has filmed in the jungle and in the middle of the Sahara, and has made films about characters who live at the edges of human achievement. "Burden of Dreams" gives us an extraordinary portrait of Herzog trapped in the middle of one of his own wildest dreams.