Tom Sugrue's fifth birthday party was interrupted when everyone went to the front porch to see the National Guard troops being driven down the street to quell the Detroit riots in 1967. For many of the next 30 years, Sugrue has been studying what brought about those events on that day.

"My parents didn't let us go out and play in front of our house, and for a 5 year old, not being allowed in the front yard is a daunting experience," he says. "I didn't fully understand why. I just knew something bad was happening."

Now an assistant professor of history at the University of Pennsylvania, Sugrue has published "The Origins of the Urban Crisis: Race and Inequality in Post-war Detroit" (Princeton University Press). Sugrue says that the urban violence and problems of the 1960s had its roots in the apparently calm and peaceful 1950s.

"To portray a city, a native must have other, deeper motives, motives of one who travels into the past instead of into the distance. A native's book about his city will always be related to memoirs; the writer has not spent his childhood there in vain."

-- Walter Benjamin.

Three social forces occurred between the end of World War II and the 1950s to wreak havoc on urban areas, says Sugrue. Individually these forces were damaging to cities, he says, but because the events were happening "simultaneously," the results were devastating. They were:

• Huge demographic changes were occurring in America, as many blacks left the agricultural south for jobs in northern, industrial cities.
• Suburbia was expanding rapidly, and urban manufacturing jobs were being relocated to rural and suburban areas.
• Intense racial conflict developed as blacks attempt to integrate neighborhoods and job markets that had been all-white.

While Sugrue focused on his native Detroit, he says many of America's other urban, industrial cities -- Cleveland, Chicago, Boston, Philadelphia -- were also affected by the same forces. "I was overwhelmed by the similarities of the situations," he says. "If I had chosen another city I could have written largely the same book."

While white Americans were better able to adapt to these changes -- by moving to the suburbs and/or with the jobs -- black Americans, says Sugrue, were victims of racial violence and hatred and were left behind in the cities.

Using records from labor unions, city council meetings, civil rights organizations, personal interviews and even neighborhood newspapers, Sugruereconstructed the personal situations for many blacks who attempted integration.

"Peel away the veneer of the '50s and you find a much more troubled and complicated society," he says.

"I found 200 violent incidents against the first blacks to integrate neighborhoods, from houses being stoned and arson to all sorts of vandalism, all committed by white people," he says. "There was a whole history of racial violence, which was largely unreported in the media.

"My neighborhood went from being all-white to predominately African-American in four years," says Sugrue. "A lot of money was made in exploiting racial fears. Blacks were willing to pay inflated prices for what they thought would be integrated neighborhoods, while whites were afraid they'd be stuck with a devalued property and were willing to sell below what their homes were worth.

"The long-term consequences are that American cities are devoid of economic opportunity, divided by race and increasingly marginalized in state and national politics," he says. "Unless there is a change in priorities by elected officials, and more energy and resources are poured into cities, then they'll be nothing more than reservations for the poor."

The debate over urban poverty, Sugrue says, is divided into ideological camps: Conservatives, he says, claim that Lyndon Johnson's war on poverty created a class who became dependent on government support; liberals argue that the exporting of jobs out of America in the 1970s and '80s took away the economic foothold of many inner city residents.

But both groups, he argues, miss the point of historical context, that events in the late 1940s and 1950s lead to the present-day circumstances of cities.

"My argument is very much one of skepticism toward attributing poverty to behavior rather than looking for an explanation in the larger economic and social changes that ravaged cities and toward the long legacy of economic divestment and racial segregation," he says.

But in addition to an historical examination, this was a personal examination for Sugrue, who analyzed his hometown and was able to better put his boyhood memories into context.

"My neighborhood underwent a very significant racial transformation. As a kid in elementary school, my best friends were black. The first blacks to move onto our block, the mother was a Detroit school teacher, and the father was a police officer. Their two kids were first black kids in elementary school, and my dad played no small role bringing them into the school and our Catholic parish, which had been all white.

"I grew up with experiences that led me to believe in racial integration. What I saw as racial integration was, in retrospect, a neighborhood changing from all white to all black. But I grew up believing in the possibilities of challenging the racial barriers that continue to divide our cities and country. It was a formative aspect of my growing up."