Hopi took 4 1/2 years to finish -- incorporating six production trips and a dozen research trips. Apart from finances, Ferrero's biggest challenge was winning the trust of the Hopi people, and then correctly interpreting their culture for the Anglo audience. To tell her story, Pat Ferrero enlisted "a network of friendships" -- Hopi families and individuals she met over a long period of time. "I only worked at places and with people who wanted to cooperate, who wanted this film to be made," Ferrero said. "It took tremendous commitment from them, just to explain to their neighbors what a film crew was doing in their home." The reluctance that she occasionally confronted, Ferrero said, stems from the early years of this century, when Hopi land was inundated by visitors. "In looking at historical photographs," she said, "you can see that outsiders outnumbered the Hopi -- that small, ceremonial plazas were overrun with photographers with tripods." Once she had established a working rapport. Ferrero faced the problem of finding individuals who would speak on Hopi history and folklore. "Hopi is organized as a series of villages," Ferrero said, "and each Village has autonomy." Even though there's a shared culture Ferrero found that "no single Hopi would presume to be a spokesperson for Hopi." Initially, Ferrero set out to make a film about women's roles. Since land use, ceremonial roles and clan membership are passed through the mother's family line, Hopi women have economic security and unusually strong social status. Eventually, though, (through the encouragement of both men and women) Ferrero chose to look at both roles, and at the importance of corn in Hopi culture. It's through corn, Ferrero said, that the Hopi maintain their strongest symbolic link to the past; and it's through the planting of corn that Hopi values are best illustrated. When the farmer plants corn, "it's seen metaphorically: The Hopi see corn as female, as a seed that's capable of regeneration. Planting is an act of faith. "Even though it's not needed for survival any longer," Ferrero added, "the Hopi still choose to plant corn, because it represents their identity. People say, 'We are corn.' I wondered how this tradition had stood up under the pressure to acculturate." Hopi ritual has survived the onslaught of Western civilization, Ferrero said, "primarily because of their isolation." The 13 Hopi villages (including the oldest continually inhabited settlements in the northern hemisphere) are built on three adjacent mesas close to the painted desert of northeast Arizona. The Grand Canyon is an hour's drive to the west. According to Ferrero, "Carbon dating shows that they've been there since the 10th century, though they say they've been there longer." I'd say the Hopi are the most intact native American group." Still, since all native American children attend Bureau of Indian Affairs schools, the Hopi frequently struggle between the need to preserve their own ways, and the wish to explore technology and newer fashionable Anglo ways. "They have TVs, cars and jobs," Ferrero said. "There's a wide range of sophistication among the Hopi." The "fourth world" referred to in Ferrero's title derives from the Hopi belief that the world has been destroyed three times by mankind's greed and corruption. The Hopi believe that they re-emerged from the earth -- just like corn -- at the beginning of the current cycle. The reference to songs is also important, Ferrero said, "since singing is really their way of storytelling. There is no written history." The soundtrack for her film, in fact, is dominated by two elements: The sound of the wind and the recorded voices of Hopi chants and songs. "I feel that our culture is at a time of great disillusionment -- almost a paralysis," Ferrero said, "and we seem to have few tools with which to cope with change. Hopi has always dealt with change in an immediate, personal way: this is a lesson that native cultures can teach us.