To reach Supai, Arizona, you turn off Highway 66 at Peach Springs, follow the mail truck 65 miles across the desert to the edge of the Grand Canyon, and then wind your way by packmule to the Canyon floor a mile below.

Supai is inacessible all winter: the dirt roads are washed out and the cliffs are slicked with ice. The Havasupai Indian tribe close the half-dozen tourist cabins they operate, send their children to the government boarding school, and tend their few sheep.

There are only 250 Havasupai in the Canyon now; brothers and cousins have gone to Flagstaff, to Albuquerque, to Los Angeles. Still tourist trade is good during the summer. The men lead packmule trains up and down the Canyon and the women maintain the cabins.

One white couple lives in Supai; she teaches primary school while he serves as postmaster-doctor-county agent. They are gossiped about but the Havasupai share with them the scrawny produce of front yard gardens.

Each spring, two Harvard-Radcliffee students descend the Canyon walls to spend three months in Supai. Usually the students have never been farther west than Pittsburgh. The West, they think, must be no more complex than jostling down a narrow trail on a donkey piled with gear, or pulling catfish out of the Colorado River above the rapids.

They enter the Canyon with no notion of what they are to do for the summer. Phillips Brooks House has promised to pay for their maintenance while they "assess community needs" and develop projects to "mobilize community interest."

Yet the Havasupai are not open about their needs or articulate about their ties to the valley and their overwhelming curiosity about the world beyond Peach Springs. The Havasupai are particularly sceptical about any white man's wanting to pass a burning summer with them, shut away from the world.

Harvard volunteers are received graciously by the tribe, but the Havasupai are reluctant to confide their fears about what is happening to their dwindling poulation, to their tenuous economy, and to the precious Canyon that is threatened by a dam upstream.

For Supai simply isn't as isolated as its location might indicate. The students quickly learn that some welfare checks are spent on liquor and that the "battered child syndrome" exists outside Soc Rel 150 texts.

This particular kind of poverty is as unfamiliar to Harvard students as the West and the Canyon. The Huvasupai subsist on Stone Age agriculture. What they know of towns and civilization is the backsides of the silver boomtowns on Highway 66: cheap wine, pool halls, dusty '51 Pontiacs parked near pseud-adobe cafes, hostility from merchants who won't give Indians credit.

Only in the desert and within the walls of their plateau, property of the tribe for centuries, do the Havasupai feel comfortable. Yet the world beyond Highway 66 is now beginning to shatter that security. The Grand Canyon Dam is rising up river, meaning water and power for California. The Havasupai lands won't be flooded, but their rapids will disappear and the familiar will be rendered strange.

Weeks pass beroe the PBH volunteers understand the tribe's particular schizophrenia. Women befriend them, confide a husband's concern about his brother who is picking oranges in California. A member of the Tribal Council confesses his complete inability to present the Havasupai's case to a government determined to go ahead with plans for the dam.

The volunteers realize, after a month, perhaps, that they can't "mobilize community interest" and solve Supai's problems. The Havasupai have begun to understand the decision they must make -- whether to commit themselves to maintaining the tribal ways in their canyon or to abandon Supai and follow the already-flown. But they postpone that decision.

PBH volunteers are not authorized

The Harvard-Radcliffe students quickly learn that some welfare checks are spent on liquor and that the "battered child syndome" exists outside Soc Rel 150 tests. to confront the federal government and argue against the dam (Stuart Udall's "baby," they observe). The tribe has no notion of how to organize itsel