Across the country, this shift in strategy has saved a few economically desolate rural towns that have become homes to the new prisons. It has also lined the pockets of corporate giants such as AT&T, which controls the lucrative pay phones in prisons. (Inmates now spend an estimated $1 billion a year on long-distance phone calls.) And it has made millionaires out of many savvy, and quite a few plainly unscrupulous, wardens who have jumped ship from public prisons to new private ones, where they can cash in on stock options and take home free-market salaries and huge "consulting fees." These corporate ventures, with names such as CCA, the Corrections Corporation of America, often build prisons on spec, then rent their cells to state systems at bargain prices, snipping a few dollars a month off the cost of keeping an inmate at a public prison.

Just as the prison boom has kicked in, the national crime rate has dropped. Yet we've continued to build new prisons -- because we like them, not because we need them, argues Joseph T. Hallinan, author of "Going up the River." It's a classic case of the tail wagging the dog, he says. To do this, we've had to persuade ourselves to believe about crime "what Americans had believed about communism in the 1950s: that its threat lurked everywhere at all times, and could be stemmed only by the creation of a vast military-industrial complex -- only now it was a prison-industrial complex."

There are, of course, other factors at play in the prison boom: The crime rate may have fallen steadily in the last decade, but the length of the average prison sentence has gone up. Hallinan, a journalist who has been writing about the criminal justice system for almost a decade, shows how the rise of mandatory-sentencing laws, in particular those for drug offenses, took discretion away from experienced judges, eliminated mercy and stuffed prisons with nonviolent offenders serving long terms with no possibility of parole. In 1995, the average prison term served for homicide was six years; for selling crack cocaine, it was 11.

Life behind bars, meanwhile, has become all the more degraded, Hallinan reports. In some maximum-security units, inmates regularly pelt guards with feces, urine and food; the guards wear safety glasses. In several state systems, such as Illinois', well-organized gangs effectively run prisoners' daily lives, terrorizing and raping the weak, even controlling cell and work detail assignments, all the while overseeing the drug traffic back home from their phones while guards look the other way.

Maya Angelou reads from "The Heart of a Woman"