He sold marijuana for his parents, he said, left school in the sixth grade and later dealt heroin and cocaine. He was for decades addicted to heroin, he said, easily keeping the habit during three terms in prison. But during his last long stay, he also studied hard to get a G.E.D. and an associate's degree.

Now out for 18 months, Mr. Baker is living in a home for recovering drug addicts. He is working a $10-an-hour warehouse job while he ponders how to make a living from his real passion, drawing and graphic arts.

"I don't want to be a criminal at 50," Mr. Baker said.

According to census data, there are about five million black men ages 20 to 39 in the United States.

Terrible schools, absent parents, racism, the decline in blue collar jobs and a subculture that glorifies swagger over work have all been cited as causes of the deepening ruin of black youths. Scholars — and the young men themselves — agree that all of these issues must be addressed.

Joseph T. Jones, director of the fatherhood and work skills center here, puts the breakdown of families at the core.

"Many of these men grew up fatherless, and they never had good role models," said Mr. Jones, who overcame addiction and prison time. "No one around them knows how to navigate the mainstream society."

All the negative trends are associated with poor schooling, studies have shown, and progress has been slight in recent years. Federal data tend to understate dropout rates among the poor, in part because imprisoned youths are not counted.

Closer studies reveal that in inner cities across the country, more than half of all black men still do not finish high school, said Gary Orfield, an education expert at Harvard and editor of "Dropouts in America" (Harvard Education Press, 2004).

"We're pumping out boys with no honest alternative," Mr. Orfield said in an interview, "and of course their neighborhoods offer many other alternatives."

Dropout rates for Hispanic youths are as bad or worse but are not associated with nearly as much unemployment or crime, the data show.

With the shift from factory jobs, unskilled workers of all races have lost ground, but none more so than blacks. By 2004, 50 percent of black men in their 20's who lacked a college education were jobless, as were 72 percent of high school dropouts, according to data compiled by Bruce Western, a sociologist at Princeton and author of the forthcoming book "Punishment and Inequality in America" (Russell Sage Press). These are more than double the rates for white and Hispanic men.

Mr. Holzer of Georgetown and his co-authors cite two factors that have curbed black employment in particular.

First, the high rate of incarceration and attendant flood of former offenders into neighborhoods have become major impediments. Men with criminal records tend to be shunned by employers, and young blacks with clean records suffer by association, studies have found.

Arrests of black men climbed steeply during the crack epidemic of the 1980's, but since then the political shift toward harsher punishments, more than any trends in crime, has accounted for the continued growth in the prison population, Mr. Western said.

By their mid-30's, 30 percent of black men with no more than a high school education have served time in prison, and 60 percent of dropouts have, Mr. Western said.

Among black dropouts in their late 20's, more are in prison on a given day — 34 percent — than are working — 30 percent — according to an analysis of 2000 census data by Steven Raphael of the University of California, Berkeley.

The second special factor is related to an otherwise successful policy: the stricter enforcement of child support. Improved collection of money from absent fathers has been a pillar of welfare overhaul. But the system can leave young men feeling overwhelmed with debt and deter them from seeking legal work, since a large share of any earnings could be seized.

About half of all black men in their late 20's and early 30's who did not go to college are noncustodial fathers, according to Mr. Holzer. From the fathers' viewpoint, support obligations "amount to a tax on earnings," he said.

Some fathers give up, while others find casual work. "The work is sporadic, not the kind that leads to advancement or provides unemployment insurance," Mr. Holzer said. "It's nothing like having a real job."

The recent studies identified a range of government programs and experiments, especially education and training efforts like the Job Corps, that had shown success and could be scaled up.

Scholars call for intensive new efforts to give children a better start, including support for parents and extra schooling for children.

They call for teaching skills to prisoners and helping them re-enter society more productively, and for less automatic incarceration of minor offenders.

In a society where higher education is vital to economic success, Mr. Mincy of Columbia said, programs to help more men enter and succeed in college may hold promise. But he lamented the dearth of policies and resources to aid single men.

"We spent $50 billion in efforts that produced the turnaround for poor women," Mr. Mincy said. "We are not even beginning to think about the men's problem on similar orders of magnitude."