IN HIS UNITED NATIONS OFFICE HIGH above New York City, Maurice Strong pulls back one cuff of his business suit and reveals a frayed white string around his wrist. Last October, while in Brazil planning for the upcoming Earth Summit, Strong was visited by several Amazonian tribal leaders. "It was very moving," says the U.N. official. "They told me their prophets had forecast a day when the white people would be in trouble and would need their knowledge to save the earth. They had heard that a great council would be convened and that I would carry their message there. A lady chief embraced me, and they tied this woven strand around my wrist with a special knot, a symbol of their trust."

Strong, 63, hopes to honor that trust. This week, as secretary-general of the U.N. Conference on Environment and Development, he will summon 100 world leaders—including a once reluctant George Bush—to the largest and most ambitious environmental conference in history, a 12-day Earth Summit at which 175 nations will try to chart a unified course to slow the degradation of the planet.

Strong has played a crucial role, in large part by working hard to bring new voices to the U.N. decision-making process—from wealthy Swiss industrialist Stephan Schmidheiny to Vandana Shiva, a supporter of India's Chipko movement, in which Himalayan women embraced trees to stop logging devastation. His own eclectic background—from Arctic fur trader to millionaire businessman and U.N. diplomat—has enabled Strong to move effortlessly between the industrialized world, developing countries and even primitive tribes. "Maurice has so much experience in so many of the areas being discussed that people can't dismiss him," says Audubon's international director, Frances Spivy-Weber.

Still, getting nations to talk will be a lot simpler than getting them to sacrifice short-term economic goals for long-term global well-being. Central to the negotiations—on crucial issues such as global warming, deforestation and biodiversity—is the deep rift between countries in the industrialized Northern Hemisphere that are resisting limits to the pollution they generate and developing Southern Hemisphere countries that are demanding money and technology to help them become better environmental citizens. "In creating wealth, the North has created the principal global risks," says Strong. "The developing countries share in those risks; they should share in the benefits, too."

Strong's awareness of the gap separating rich and poor began during his childhood in Oak Lake, Manitoba. His father, Frederick, a telegraph operator for the Canadian Pacific Railway, lost his job in the Depression, and the family sank deep into poverty. "We had no plumbing, no heat," says Strong, the eldest of four children, who used to pick coal off train tracks for the family stove. "I had a great sense that wasn't right. There had to be a better way."

Restless by nature, Strong ran away from home at 14 in search of a career. He recalls later picking up an old newspaper in a freight yard in Saskatchewan with an article about the fledgling United Nations. "The idea captured me," he says, "the idea that we could weld together a world coming out of a terrible war. It became central in my life."

But it had to wait while he pursued more immediate opportunities. He signed on as an apprentice fur trader with the Hudson's Bay Company and was posted to the Northwest Territories. There, as a protest against what he perceived to be his manager's patronizing treatment of the native people, he moved out of the trading post to live among the Inuit. "They were innovative, creative people," he says. "I learned a lot from the way they dealt with each other and with nature."

In the late '40s, Strong moved to Calgary and took a job in the Canadian petroleum industry. A few years later, he started his own company, and by 1964, at age 35, he was president of Power Corp. of Canada, one of the country's largest investment conglomerates. After a stint as director of Canada's International Development Agency, Strong finally realized his boyhood dream: U.N. Secretary General U Thant asked him to lead the first U.N. Environment conference in Stockholm in 1972.

That same year, Strong, who was divorced from his first wife, met Hanne Marstrand, a Danish designer living in New York City. "At our first dinner he asked if I had heard of him," says Hanne. "I told him, 'Yes, I've heard two things: One, that you're a terrible fake. The other that you're a genius.' Maurice laughed and said, 'Well, you'd better find out for yourself.' "

Strong and Marstrand married in 1981. Their children by their previous marriages now grown, the couple divide their time between a house in Geneva, Switzerland (where the main Earth Summit offices are located) and a 200,000-acre ranch in southwestern Colorado, where they are establishing an ecumenical spiritual retreat that will include a Zen center, American Indian ceremonial lodges and a Hindu temple. "Maurice has the strongest will of any person I've ever met," says Hanne. "Unlike most people, he can manifest his dreams."

Strong's current dream is for a new environmental world order arising from Rio. "My greatest hope is that the government leaders will adopt the proposals in front of them and implement them," he says. "My greatest fear is that they will adopt empty treaties but present them to the world as successes. The world must hold them accountable."