An inventory of the lost Suppose your father was working high in the World Trade Center on Sept. 11, 2001. You have been told by authorities in New York City what intuition told you as you watched the two towers collapse: Your father is dead. Yet that conclusion is a municipal bureaucracy's intuition, no more certifiable than your own. Your father's remains have not been found. He is presumed to have been killed largely because, first, he could not possibly have survived and, second, he has not been seen since.

So your grief is compounded by a question as illogical as it is impossible for you to shake: What if, somehow, he escaped? What if, in some perhaps tragicomic way that screenwriters might never imagine, he managed to get out alive? This sort of bizarre ending doesn't often happen in real life, of course. Extremely rare is the victim of war, or of violence, or of some other tragedy, whose remains are never found and identified.

If survivors of those victims get the terrible pain of loss, they invariably get proof that the victim is, irrefutably, deceased. Not so, though, for many survivors of the 2,792 people killed at the World Trade Center. Working with body parts retrieved from mountains of rubble, the office of New York City's medical examiner has confirmed the identities of 1,518 of those World Trade Center victims. But scientific tests have failed to link any of the body parts to the more than 1,200 other victims. The majority of those body parts exhumed from the debris - 12,000 of almost 20,000 fragments - are a tragic inventory of the lost. Efforts to match them to known DNA samples provided by the families of victims - strands of hair lifted from combs left at home, for example - have failed, often because the retrieved body fragments were so badly incinerated, crushed or deteriorated that their DNA was unknowable.

Unknowable, that is, using today's DNA technologies. Faith in future technologies has led to a remarkably smart way of dealing with all those still unidentified body parts. They are being dried, individually vacuum sealed and packaged for a time when new means of identifying human tissue may tie them to specific victims. Under a protocol developed by city officials working with representatives of victims' families, the remains will be interred in a memorial at the site of the twin towers. If the science of tissue identification advances, those remains can be removed and examined anew. The quest to identify remains addresses the need that many families feel for some sort of denouement, or closure.

Some survivors want unambiguous proof of death. Others, forced to hold memorial services without subsequent burials, want any remains they can inter. 'When you have no remains, it's important to have someplace you can go,' says Nikki Stern of Families of September 11, an advocacy group that represents the interests of survivors from 46 states and several nations. 'Under this plan, the unidentified remains will be in a place families can visit. ' Part of what's driving the families, Stern says, is a yearning she sums up as, 'How do you control the uncontrollable?' These are not, after all, the families of soldiers or astronauts who appreciate the risks of their jobs. These are ordinary families, stripped of their loved ones and forced to revisit their losses at occasional intervals.

Last week's disclosure of transcripts of emergency calls from the morning the World Trade Center was struck by two aircraft is only the latest rip at their heartstrings. Finding a means for preserving an inventory of the lost is of crucial interest only to the families of those who died on Sept. 11. But given all that the survivors have endured, it's a small achievement the rest of us can applaud..