Louisa Kennedy never told anyone that the first letter she received from her hostage husband amounted to little more than a last will and testament.

Mary and Jesse Lopez kept secret the fact that their son's heroism had enabled six other Americans to escape the day the embassy was seized.

And Barbara, Jerome and Joseph Holland lived for 14 1/2 months in Cincinnati with only their closest friends learning that their father was a hostage.

Secrets. Almost from the moment word flashed around the globe that the 52 American hostages were free at last, these tales of heroism, private suffering and horror, withheld from the public in many cases because they might have angered the Iranian captors, began bobbing to the surface.

Some were secrets the hostages had kept from their captors, small things, such as how they communicated with each other when forbidden to talk. Others were secrets kept from the hostage families by government officials who did not want to alarm them unduly.

And some were secrets the families kept from their neighbors and the public because they valued their privacy or feared that word might get back to the Iranians and cause harm to their kin.

"For obvious reasons, they [the State Department] didn't want [all information] publicized because it . . . could have had possibly dangerous ramifications," said Kennedy, who is the chief speaker for the organization representing the hostage families.

"This [sort of information] was all kept from us. And I think rightfully so," she said. "Again, you're under a situation where knowing it is not going to help any of us. What can we do about it?"

Early this week, former State Department spokesman Hodding Carter said that the government also kept secret details of the hostage situation in an effort to protect its sources, who otherwise would have been cut off had the information been revealed.

Air Force Staff Sgt. James Hughes, one of the 13 hostages freed shortly after the American Embassy was seized, had to fight off the temptation to talk about the treatment he and others received at the hands of the militants whenever he heard the Iranians claim that the hostages "were livng in luxury, how well they were treating them," he said yesterday.

"Well, if that was so, things sure changed after I left," said Hughes, who is stationed at Langley Air Force Base in Hampton, Va.

But common sense -- not orders -- kept him from discussing his experiences. "You have concern about those people [in Iran], those families," he said. "It wasn't hard."

For Kennedy, the reality of the situation became apparent to her in January 1980, when she received her first letter from her husband.

"The first letter I had from my husband . . . was more or less a last will and testament," said Kennedy, whose husband, Moorhead Kennedy Jr., was an economic and commercial officer for the embassy. "He said he was willing to accept this with serenity and die if necessary in the cause of the country. But the rest of the letter was just fond last remarks. So I knew from early on."

The Lopez family learned that Mnarine Sgt. James Michael Lopez, 22, had been a hero when six Americans who had managed to flee to the Canadian Embassy durng the seizure of the U.S. Embassy arri flee to the Canadian Embassy during the seizure of the U.S. Embassy arrived back home three months later.

The six publicly related how they had managed to escape thanks to the help of several Marine guards. But they did not identify them.

However, Mary and Jesse Lopez, of Globe, Ariz., learned at the time that their son was largely responsible for the escape of the six.

According to accounts, Lopez was at the consulate at the time of the militants' attack. He barricaded the doors and hurled tear gas grenades to hold off the Iraniansw, enabling the six to escape. He was later captured, however.

When Lopez was able to telephone his family from Germany this week, his younger brother, Danny, promptly asked him about his role in the escape. "Don't talk about that junk," Danny quoted his brother as saying.

Yesterday it was learned that Lopez also had scrawled on his cell wall, while a hostage, "Viva la roja, blanco yazul" -- Spanish for long live the red, white and blue. He had written it in Spanish, certain that the Iranians would not understand what it meant.

When Barbara, Jerome and Joseph Holland learned that their father, Army Col. Leland Holland, chief of security at the embassy, was among those taken hostage, they decided that they would rather remain anonymous than suffer continual public scrutiny.

"We didn't see ourselves as poor people," said Barbara Holland, 26, a physical therapist. "We didn't want to wallow in self pity: 'Our father's a hostage, poor us,' because, if you do that, there's no end."

So the three children lived quietly in Cincinnati, two of them in an apartment directly underneath the apartment of two television reporters. The reporters never learned who their neighbors were. The children's mother, Mary Ann Holland, and three younger siblings live in Laurel, Md.

"It was like being a fly on the wall," Barbara Holland told the Associated Press. "It would permeate conversation whereever we'd go . . . to a supermarket or the symphony. It was so nice. They were caring. It was nice because they showed they cared even though they didn't know we were here."

Walter Schaefer, a retired military chaplain, was ordered by the government to keep silent about the fact that his brother, Col. Thomas Schaefer, 50, was among those seized as a hostage. The reason: the government believed that his Iranian captors were not aware of the fact that Col. Schaefer was the top military official at the embassy. If discussion about him could be kept to a minimum, his position might continue a a secret.

Over the next 14 1/2 months, the elder Schaefer, a resident of Colorado Springs, told only the closest of his friends about his relationship with Col. Schaefer. He had no contact with his brother during that period, and the State Department announced only that Col. Schaefer was from Tacoma, Wash., married, and the father of two.

For the families of the hostages, the isolation and ignorance of what was happening in Tehran were sometimes a blessing, according to Kennedy. She said Richard Queen, the hostage who was freed after 250 days because of medical reasons, "told us the minimum. I mean, we were aware that all was not roses and cream with Richard, but he chose to dwell on the items or the effects of it all that we could handle.

"He told us things they were able to pass messages in the bathrooms, I think, or in the corridors . . . although they were told not to talk. They took the chance of talking and sometimes getting slapped down for it. I guess," she said. "It's going to be hard to accept it all, I think. I hope that they, truly, I hope that the hostages will dwell on some of the more positive aspects of what went on there as well as the bad things."

Some former hostages may never tell about all their experiences, however.

"I have some [secrets] I'm still keeping," Sgt. Hughes said yesterday. "My personal feelings about some things that happened . . . that I won't even tell my wife about.

"I may never tell anyone," he said.