FIFTEEN HUNDRED MILES from the nearest flicker of civilization, in the depths of the Peruvian jungle, a mile-long clearing has been hacked to connect two rivers. On one bank rests a 300-ton steamship with its nose pointed up the 40-degree slope of a mountain, looking like a stranded whale waiting to climb a steep beach. A series of ropes connect the ship to massive human-powered wooden winches and a lone bulldozer. The engineer, who designed the system to tackle a 20-degree grade, has quite fearing for the lives of the Indian workers if a metal clasp or something else should snap. Although the director has been told repeatedly that he is attempting the impossible, he perseveres, ignoring the dangers, refusing to consider abandoning his dream.

This director bears no resemblance whatsoever to his armchair counterparts in Hollywood. For Werner Herzog, filming his latest effort Fitzcarraldo, only hauling this massive ship over the mountain would properly illustrate the central metaphor of his movie. Perpetually choosing the most difficult route possible to achieve his goals, Herzog scorns the shortcuts and props that usually dominate his medium.

Les Blank's documentary, Burden of Dreams, which opened last Friday at the newly renovated Brattle theater, captures Herzog and his crew fighting both to create a movie and retain their health and sanity while entrenched in the primitive jungle. Beware of dismissing this movie merely because it falls into the category of "documentary." It is a fascinating portrait of a director straddling the border between sanity and the depths beyond, while challenging himself and nature through the jungle.

The plot of Herzog's Fitzcarraldo, which has yet to open in Boston, in turn follows the real-life story of bankrupt Irishman who dreams of producing the operas Carcuso in the Brazilian jungle. To raise the necessary capital to back his production, he decides to cash in on the rubber boom by taking a steamship to virgin tracts of jungle, carrying it a mile overland to an otherwise inaccessible river. The real Fitzcarraldo (so named because the natives could not pronounce Fitzgerald) cut a 20-ton steamship into 15 pieces to accomplish his made task. Herzog, in his reenactment, does not regard that as enough of a challenge, opting to haul a 300-ton steamship in one piece.

Burden of Dreams looks frankly and directly at the obsessed Herzog, who despite frequent troubles continued to struggle for his movie. Seeing no alternatives, he says, "I live my life and I end my life with this project." Throughout the four years spent on the film, a continuous series of problems plagued Herzog's efforts. Once he and his crew were forced to flee camp for their lives; later original actors Jason Robards and Mick Jagger pulled out, the former because of ill health, the latter for other commitments. Herzog had to start from scratch with a new lead, Klaus Kinski, while writing out Jagger's obviously irreplaceable part.

BLANK, however, artfully presents much more in Burden of Dreams than merely Herzog's warped world. The movie contains beautifully photographed scenes of one of the most primitive sports on earth as well as glimpses of the culture of the local Indians and the problems they confront as the modern world encroaches on their territory. Herzog hired many natives as extras and laborers, and the practice created typically Western dilemmas over how to run the camp where both Indians and film crew lived. Should the rules of Western society or the laws of the jungle take precedence? Herzog's pursuit of authenticity raises many such questions, which only a true purist must face.

Whether or not Herzog succeeded in making Fitzcarraldo an impressive movie or not remains to be seen, but only if it's extraordinary will it stand a chance of surpassing Burden of Dreams. In today's world of high budgets and slick plots, Burden of Dreams vividly reminds us of the myriad powerful emotions and captivating scenery one can achieve through non-fiction.