The world's 200 richest people have doubled their wealth in just four years, and the assets of the three richest families now exceed the combined gross national products of all the least-developed countries, according to a U.N. report released today.

"Global inequalities in income and living standards have reached grotesque proportions," says the Human Development Report, an annual survey that focuses this year on the costs and benefits of globalization, a vaguely defined term that includes developments as diverse as the liberalization of markets and the expansion of the Internet.

The report concludes that globalization created unparalleled riches over the past 50 years, tripling average incomes and boosting global GNP from $3 trillion to $30 trillion. But the benefits have been uneven and the disparities are growing, it says.

As of 1998, three leading billionaires -- Microsoft's Bill Gates, the Sultan of Brunei and the Walton family than owns Wal-Mart -- had amassed at least $135 billion in combined assets, more than the total GNP of all 43 countries categorized by the United Nations as "least developed," said Sarah B. Burd-Sharps, spokeswoman for the U.N. Development Program, which produces the report.

While the world's 200 richest people doubled their wealth to $1 trillion from 1994 to 1998, more than 1.3 billion people in the developing world eke out a living of less than one dollar a day, the report says.

The explosive growth of the Internet -- from 143 million users in 1998 to a projected 700 million in 2001 -- is generating wealth and job opportunities in many countries. But, the report notes that more than 88 percent of Internet users live in the industrial world and about 80 percent of all Web sites are in English, a language spoken by fewer than 10 percent of the world's people.

The 260-page report warns that the United States and other leading industrial nations face a potential threat to their security if they fail to redress imbalances in wealth, trade and education.

It recommends creating a legal office to help poor countries negotiate trade pacts. It proposes the establishment of a joint World Bank-U.N. task force to narrow economic disparities. And it appeals to the industrial powers to restore dwindling aid to poor countries.

If the world's 200 richest people each donated 1 percent of their wealth per year, the report says, they could ensure access to primary education for every child in the world.

The report, which includes a global quality-of-life index, places Canada, Norway and the United States at the top of the list of countries with the highest quality of life, based on life expectancy, access to education and average income. Sierra Leone, where the average life expectancy is just 37 years, is at the bottom of the list.