Kia, a Khmer boy born in 1967: "Separated from parents in 1975." Moeun, another boy the same age: "Lost contact with his family during attack on his village." Wanna, born in 1966: "Seperated from family in 1978 to work as farmer."

These are three boys among 2,737 children whose dossiers are reporduced in white-covered books circulating in Cambodian refugee camps in Thialand. Each entry includes a photo and, if the child is old enough to give them, a name, a list of family members and a bit of personal history.

They are "unaccompanied minors," official parlance for refugee children who arrived in Thailand without parents. The books, far from being a directory for adoption agencies, are helping parents locate missing sons and daughters.

Ever since they began crossing into Thailand last year, part of an exodus that brought 150,000 Cambodians to U.N.-financed camps, the children have created controversy. This month it happened again -- refugee workers discovered that about 140 children had vanished at night from children's centers in two camps near the Cambodian border.

In both Kamput and Meirud, agents of the ousted Khmer Rouge government run a shadow administration.The assumption is that the missing children were taken to Cambodia to rejoin relatives or serve the Khmer Rouge as soldiers, laborers, or spies.

For many the return may have been voluntary. During the years the Khmer Rouge ruled Cambodia, about half the children now in the centers were inducted into mobile children's teams, formed to roam the countryside performing collective work and learning the tenets of revolutionary life. Blind loyality to adults in charge was often imbued in the young team members.

A spokesman for the Thai military's Supreme Command, which has jurisdiction over the two camps, denied any knowledge of the minor's disappearance. But the local Office of the U.N. High Commissioner for Refugees, which oversees the feeding and protection of refugees, acknowledged it.

"The government has given assurances that measures will be taken to prevent any future moves of this kind," a spokesman for the U.N. commission said.

Since new security measures went into force Nov. 5, no further departures of minors have been reported, the spokesman stated.

The United Nations is also considering moving the children to camps further away from the border, according to the spokesman.

News of the disappearance of the 140 children enraged many refugee workers and brought to the fore -- again -- some familiar questions:

How long does it take to satisfactorily establish that a child's parents are dead? How long should a child be held in an insecure camp until he is cleared for resettlement in a third country?

Almost everyone working with refugee agencies here has strong opinions on the subject. Those who favor speedy resettlement are vilified as "orphan hunters," quick to steal the sons and daughters of absent parents. Those favoring time-consuming efforts at tracing are called heartless bureaucrats who leave children to languish behind barbed wire.

For the present, the lengthly search approach prevails. The U.N. commission spokesman said the fate of the 140 children would not persuade it to abandon efforts to trace parents.

Last December the United Nations effectively froze resettlement of unaccompanied minors, after 300 were taken to France and West Germany. U.N. officials felt only superficial efforts had been made to locate parents.

Arrayed against the United Nations are some Western embassies, foreign adoption agencies, church goups and a few individuals who fly in from abroad to try to get acton on specific cases. a

U.N. officials point to reunion statistics as proof their approach is justified. Of about 2,500 children originally classified as unaccompanied minors, 1,078 had been reunited by Nov. 15 with parents, siblings and in some casesaunts, uncles or grandparents, U.N. figures show.

"The data show that the majority have family," said Everett Ressler, Thailand's representative of Norway's Save the Children foundation, which the United Nations commissioned to produce the tracing books.

Ressler said that of more than 2,000 children interviewed, only 37 percent claimed that both parents were dead. The actual figure may be far lower, he argued, because many children had no direct word of their parents' fate. More than half the children simply said they had been separated.

Tracing is continuing. Social workers carry the books directly into refugee households and watch as adults peruse them. At other camps, bulletin boards crowded with photos of the children are visited by searching parents.

U.N. officials report that some adults make special trips to the Thai frontier from the Cambodian interior to check for missing children. By the end of October, 42 cases of family reunion at the border had been recorded, 25 of them involving parents.

The United Nations' critics hold that tracing is necessary but that it is criminal to put open-ended delays on permanent solutions for those children with no realistic hopes of finding fimilies, and who themselves want to go overseas.

Some critics, like Tim Bond, affiliated with the relief organizaton Terre des Hommes, have questioned the U.N. practice of putting children in Khmer foster homes. In an interview, he argued that in view of Cambodia's poverty and the potential for continuing war, Khmer parents cannot guarentee a child's welfare, and preference should go to sending confirmed orphans abroad.

Sentiments like these have led to concerted pressure from embassies in Bankok to make the United Nations free children for resettlement. "It comes to a crisis stage about every two months," said one diplomat whose embassy is frequently asked to intervene.

Partly to relieve this pressure, the United Nations this summer began quietly processing small numbers for resettlement. Close to 40 have gone, most of them aged 4 or less, too young to give information to help in tracing and, in many cases, to be recognized by family members.

Tracing interviews found that during the four years the Khmer Rouge ruled Cambodia about half the children were taken from their families and put into children's mobile teams. These special work and political study units were intended to mold future generations of dedicated revolutionaries.

Teams were abandoned by their Khmer Rouge overseers when Vietnamese forces seized the country in 1979. Fending for themselves, the children wandered from village to village before crossing into Thailand; many had long since come to think of their parents as dead.

Although some children remain loyal to the Khmer Rouge, most seek the peace and contentment that they, like everyone else in the camps, hear exists in the United States and Europe.

One boy scheduled to go to West Germany last year from Meirud Camp was dismayed to learn his mother arrived just before departure time. Removed from the lists, he refused to live with her in the camp and returned to his place in the children's center.

Corruption and parental deceit create further problems. Countries that take minors sometimes agree to accept members of the same family who show up at a later date. Thus some families put children in the centers with the plan that the child will go abroad and then request that his of her "newly discovered" loved ones follow.