WEST LAFAYETTE, Ind. -- The Y2K computer bug pales in comparison with another challenge to be faced in the new millennium, says a Purdue University sociologist.

America is quickly becoming a two-class society, argues sociology professor Robert Perrucci, with 20 percent of people at the top and 80 percent at the bottom.

This new class structure is making more Americans poor and powerless and is designed to keep them that way.

'Over the past 25 years, the American Dream of rising to the top has taken a severe beating,' says Perrucci, co-author of a new book, 'The New Class Society,' written with Earl Wysong, a professor of sociology at Indiana University, Kokomo.

Downsizing, technological advances and globalization have all taken their toll on the working class since the 1970s, he said. 'Those not already in the upper-privileged class find it very hard to get there.'

The authors say America's new class structure is a 'double diamond,' not the traditional single diamond image that most people have of class structure in the United States, with people rising or falling among the ranks according to their personal achievements.

In this double diamond, 20 percent of society, which occupies the top diamond, enjoys the perks and security that come with access to stable financial and social resources. Below that diamond is a much larger diamond, connected to the top diamond by a very narrow opening, which represents the 80 percent of society that face job insecurity and limited financial resources, with little chance of rising to the top.

'There has been a tremendous shift of wealth in the past 25 years from the majority of the population to the very few,' Perrucci said. 'The resources of those in the top diamond are used to maintain and legitimize the new class system. That's because they control the economy, politics and culture.'