Listen to the voices of the hostages: "I've been outside only once without a blindfold. It would be great to see the sun again" -- vice consul Donald J. Cooke, 24.

"We still cannot speak to each other -- which is the most unbearable restriction, given the need for human contact" -- U.S. press attache Barry Rosen, 36.

"It is difficult writing with these cuffs on" -- communications officer" William E. Belk, 43, in a tense footnote.

As letters and Christmans cards began streaming into the United States in recent weeks from the American hostages in Tehran, a stark picture emerged of life in the U.S. Embassy that has served as their prison since Nov. 4. The letters contain some disquieting notes, but also some words of reassurance.

The hostages speak of boredom and solitude, inadequate exercise, insomnia and occasional illness, starchy food and loss of weight. They say, in some instances, that their hands remain tied. They complain of a lack of news from the outside world. They appeal for U.S. help to free them.

But some letters also say that living conditions improved after the first month of confinement. The hostages note that a doctor has visited them. They do not indicate any physical abuse by their captors, and some letters specifically say no U.S. diplomat has been tortured. The hostages tell their families that they are all right.

"I eat, sleep and rea, and I'm well," political officer John W. Limbert Jr., 36, noted in a Christmas card to his father. Marine Sgt. Kevin J. Hermening, 20, told his mother, "I think this is harder on our families than it is on us because you don't really know what's going on."

More than 45 of the 50 hostages believed to be held by Iranian militants have apparently been permitted to send leters or cards to their families, although some mail has not yet bee delivered.The letters, which began arriving in mid-January, represent the mose extensive contact yet between the captives and the outside world.

Previously, communication from the hostages had been limited and highly selective. Marine Cpl. William A. Gallegos was interviewed by NBC television Dec. 10 and said that most hostages "haven't been mistreated." Four hostages later read statements for Iranian television cameras, calling for the former shah's return to Iran for trial. The statements were quickly denounced by U.S. officials as staged.

Three American clergymen were allowed to hold Christman services for 43 hostages and to return with brief messages for their families. A few hostages were permitted to send out other notes or tape recordings, and several made telephone calls to the United States.

But the recent flurry of letters marked a departure. "All of a sudden we have been told that we can write a letter," one hostage wrote. The State Department expressed hope that the letters indicated a new willingness by Iranian militants to allow their captives to communicate with the outside world.

Among the first letters to arrive was one mailed to The Washington Post by consular officer Robert C. Ode. 64, of Falls Church. The oldest of the hostages. Ode appealed for "prompt action to free us from this terrible situation." He spoke of nearly sleepless nights, a lack of news, and days and nights spent with his hands bound.

Ode's letter was not the only one to describe living conditions in the embassy in harsh terms.

"I don't know how much longer I can hold out because the Marines I'm locked up with -- we all came down sick," Marine Sgt. John D. McKeel Jr., 26, wrote to his parents in suburban Dailas. "I have lost 25 pounds and am as thin as a board ...

"The guards here are crazy. They have machine guns and shot guns and they go around shooting up the place."

The hostages also frequently say they feel abandoned. "I'm sure we're on page 19 of The Washington Post and the L.A. Times but please try to keep us on the front page," general services officer Gary E. Lee, 36, wrote to his wife in Falls Church. " know the American public. Sometimes their memory is short."

It remains unclear why the hostages were permitted to send the letters. The messages appear to have been screened by Iranians censors. Some letters amount to typewritten appeals for deposed Shah Mohammad Reza Pahlavi's return for trial. The typewritten letters are viewed by some of the hostages' relatives as Iranian propaganda that, they believe, the captives were told to sign.

Nevertheless, many other letters are handwritten, intimate, filled with insights into the hostages' lives and are regarded by their families as authentic.

One possible clue to the letters' emergence may be their dates, ranging from early December to mid-January. The dates coincide with a time when Ayatollah Ruhollah Khomeini ordered foreign observes to be allowed to see the hostages, leading to the Christmas visit by the three clergymen. There were also persisent, though unfulfilled, reports then that some hostages might be released.

On the whole, the hostages' families say they have been cheered by the letters. They seem to show that most of the captives remain physically and mentally sound, the families say. Some letters arived by mail. Others were carried back by an Americna Indian activist who visited Tehran earlier this month.

"It's no worse than a geology field camp," vice consul Cooke, who studied geology at Ohio State University, wrote his parents in Memphis. Depsite his wish "to see the sun again" and his comment that "lack of contact with the outside world is a bit oppresive," his mother, Susan Cooke, found his letter "upbeat" and encouraging.

Some letters appear to reinforce reports that the hostages' captors are a less than cohesive group.

"Things would be more bearable around here if there were fewer chiefs and more Indians," Marine Staff Sgt. Michael E. Moeller, 28, the embassy's security head, wrote to his wife, Lisa, in Caruthersville Mo. "Not that they keep us confused for harassment. They just can't make up their minds what they're going to do."

Moorehead C. Kennedy Jr., 49, a veteran State Department economic officer, was among the hostages who noted signs of "considerably improved conditions" aafter the first month of confinement.

"Today was a good day, in that we had outdoor exercise, afterwards a hot shower an a chance to wash our clothes," Kennedy wrote to his family in Washington Jan. 119 "They have taken my sheets off to be washed, for the first time. These little things mean a lot."

"Also, they found me a razor," Kennedy added. "After shaving, I looked at myself in the mirror and decided that I did not look to badly; a bit thinner around the face, which is all to the good."

Nonetheless, Kennedy's letter -- like those of other hostages -- contained a note of solitude. "I have already designed in my mind several new brick walks for the garden, all with fascinating brick patterns," he wrote. "almost a mathematical exercise."