The first wave of paper rained upon the city from the World Trade Center like death's disembodied proxy. As if in answer, a second wave rose up from the photo albums and word processors of thousands of desperate families.

Fliers covered store windows and television satellite trucks; the walls outside hospitals and the carts of the homeless. They bore the names, smiling faces and intimate physical details -- the fingers like a little girl, the titanium hip -- of the missing.

The hope was that loved ones, dazed or knocked unconscious by the towers' collapse, were wandering unknown neighborhoods or lying unidentified in hospitals. But as days passed, and hope dimmed, the fliers continued to spread. People still stopped to stare at them, even though they said they no longer believed that those looking back were alive.

Manufactured in hope, the fliers now have transmuted into memorial.

''It has become for us here, and many who walk past, much like the Vietnam War memorial,'' said James Saunders, the public affairs director at Bellevue Hospital Center, where hundreds of fliers paper a construction barrier outside the hospital entrance. ''You walk past and see their faces and acknowledge that these were lives.'' And, he said, the vivacity of the photos used -- the men in tuxedos, the woman in her bridal veil, the laughter -- reinforces that they were lives extinguished early.

Some families, of course, still cling to the fliers' original intent. A week ago, two fathers, one missing a son, one a daughter, arrived at the hospital from Japan and posted pictures of their children. ''They are hoping against all odds,'' Mr. Saunders said.

But those were the last fliers he knew to be posted, and for many others, the fliers now simply present physical proof, a public statement, that the person lost was loved. They impress individuality on an event so gross in scale that an abyss of anonymity threatens the dead.

''Carol R.I.P.,'' says the green paper heart taped on top of the flier for Carol LaPlante at the Times Square station.

The almost accidental memorials are as much a product of 21st-century technology and its ways of communicating as the last-minute cellphone calls and e-mail messages on Sept. 11. In an era in which anyone with a word processor and photo scanner, or access to a copy shop, can become a publisher, people took a basic unit of conveying information -- the 8.5-by-11-inch piece of paper -- and set to work.

Often they turned to an icon of mass, and democratic, production: Kinko's 24-hour copy shops. On Sept. 11, people took photographs to be scanned, lined up for the color copier, and asked to make anywhere from 50 to 500 copies. Many stores made them for free.

But the fliers also hark back to the past. People could, and did, post information on the Internet, but they also felt compelled to put faces on paper, and put the paper on the street.

There are historical parallels. When the Titanic went down, the White Star Line posted passenger lists. New Yorkers went to see who were among the dead. During the Vietnam War, and sometimes long after, people wore bracelets engraved with the names of those missing in action, as if to say, ''We have not forgotten, or given up hope.''

People post similar fliers for missing animals. Milk cartons show photographs of missing children, with similar data -- their height, weight and age, even the clothing they had on, when they disappeared.

But, of course, there are no historical parallels. That is why, in neighborhoods where they are few in number, the fliers literally silence passers-by who for a few moments had the audacity or good fortune to forget. And why, in the usually hurried crossroads of the Times Square subway station, they have managed to make time irrelevant.

Travelers who see the fliers find themselves in extended, mute contemplation. For David Kranz, an employee of 1199/S.E.I.U., the health care union, the fliers evoke the ''whole world of people'' who knew each person. ''The tragedy is not a statistic of 6,000 people,'' he said. ''It's about so many people losing someone.''

John Shannon, a management consultant, said he knows well-off, white Wall Street people who are missing. The panoply of posters showed him that the attacks had hit people of all races and incomes.

Some people come to see if there are faces they know. One woman said she recognized a man she often saw on the subway, which reminded her of what made New York special -- that even strangers' faces could become familiar -- which in turn made her sad.

The looking has a masochistic quality. People wipe their eyes, say ''it's so sad,'' and keep looking, as if eager to feel more pain.

''I think it's very difficult not to look,'' said Munni Srivastava, 55, who was visiting from England. ''The first thing that strikes you is how young they were.''

Seeing the same faces in different places, she imagined families saying: '' 'If I just put enough of these fliers, maybe there will be a miracle.' '' She understands, she said, but ''intellectually we know there's no chance in hell.''

Public agencies like the Metropolitan Transportation Authority usually keep tight control over what is displayed in their domains. Michael Bierut, a graphic designer, said the abdication of control of public space was a powerful statement in itself. ''It is anathema to a sense of order, to institutional control over an environment,'' he said.

An M.T.A. spokesman, Al O'Leary, said, ''The feeling here is that we're going to leave them up until a consensus arises from all corners of the city that they no longer serve a useful purpose.''

The postings sprang up spontaneously, then spread like a desperate ivy. At Bellevue, five fliers first appeared on the hospital doors. Staff members moved them to the construction barrier, where they now stretch hundreds of feet, and named it the Wall of Prayers.

Christina Lynah, a secretary, came at her lunch hour on Wednesday, keeping one eye on her watch and one eye on the wall. She wanted to see if she knew anyone, praying she did not, but also to absorb both the enormity, and specificity, of pain.

''It makes you angry,'' she said. ''It makes you very angry.''

The material of memorial, of course, is fragile. Mr. Saunders said one hospital official was heartbroken when he saw that after a rainstorm, the fliers outside the armory at 26th Street and Lexington Avenue had been blurred and dropped to the ground. It seemed to him as if the tragedy had happened all over again.

Fortunately, Bellevue officials thought to cover their wall in plastic, and hope to preserve it permanently. The city's Department of Parks and Recreation has also been collecting materials left on its property. ''It may be ephemera, but there are ways,'' said Deborah Waters, the chief curator at the Museum of the City of New York. The Vietnam Veterans Memorial, for example, is annotated daily by the notes and letters of visitors; each day, the National Park Service collects and catalogs them.

In the meantime, the fliers are challenging how America remembers its dead. American gravestones are usually minimalist, impersonal, discreet: name, year born, year died. But the fliers are profuse and colorful, sometimes zany, and graphically personal, with details -- a woman's weight, the scar on an inside left thigh -- usually known only to lovers or doctors. Much like the AIDS quilt, which with each square attempted to give intimacy to large-scale loss, they imply a refusal to go sedately into oblivion.

And they stand in dialogue with another kind of poster that has spread throughout the city -- the ones showing Osama bin Laden's face, with the word ''Wanted.'' The fliers, for some, justify that hunt. But they also seem to say, don't forget: Rhondell Cherie Tankard, Stephen Joseph, Jorge Velazquez, Katsuyuki Hirai, Colleen Supinski and some 6,000 others -- they are wanted, too.

Photos: Workers at St. Vincent's Manhattan Hospital look at the faces and descriptions of the missing that are posted on a wall at the hospital. (Edward Keating/The New York Times); Fliers in the Times Square subway station, posted in hopes of finding those missing at the World Trade Center, have now become memorials. (Fred R. Conrad/The New York Times)