What does it feel like to stand naked on a chair with a hood over your head and electrodes attached to your body? And, just as important, what is the point?

To the first of these questions, history provides no answer. Jacobo Timerman, an Argentine newspaper editor imprisoned and tortured in 1977 because the regime suspected an international Jewish plot to take over the country, recalled in his memoir that even though he had grown up on stories of Nazi camps and Soviet prisons, he could not begin to guess how it felt."I knew nothing," he writes."And it's impossible to convey what I know now."

Timerman is not the only one who will not let the historian inside that experience. Many have described it as"intimate" - the brutal, frightening intimacy that one associates with rape. It is an intimacy not so much between torturer and tortured as it is within the mind of the victim, something one cannot begin to explain to others.

Timerman's fellow prisoners rarely mentioned their own torture, except"via a random remark that didn't seem of consummate interest to anyone." Both intimate and painful, the experience became a grotesque part of everyday life."Sometimes," he recalled,"on hearing the howls that rose from the basement, a prisoner might say, as if in passing, 'They're giving someone the machine."'

There are two kinds of torture, broadly speaking: torture that appears to have no purpose beyond the sadistic, and torture in which the state or other authority tries to extract information.

But the events at Abu Ghraib show there's a fine line between the two. The American soldiers guarding suspected sympathizers of Saddam Hussein or insurgent guerillas may have believed they were"softening up" prisoners to yield more information. They may also have believed they were doing so on orders from commanders who, removed from the action, were presumably interested only in information, not in sadistic pleasure. But it seems that one fosters the other: A climate of brutal interrogation makes prisoners fair game for a kick from a passing guard and the myriad little punishments of one's cellmates....