On Aug. 5, 1964, while bombing Haiphony harbor, Alvarez, a Navy lieutenent, became the first U.S. pilot shot down over North Vietnam. A POW 8 1/2 years, longer than any other American held in North Vietnam, he was tortured, isoalted for long periods of time and exhibited before jeering crowds. He got word during his captivity that his wife had divorced him to marry someone else.

''I rarely think about it -- I'm really too busy living in the present,'' said Alvarez, 47, who remarried eight months after his 1973 release. He lives in Rockville with his wife and two sons, 8 and 10, and is deputy director of the Veterans Administration.

''We were there for a good purpose, but the reality was frustrating . . . It was a political scenario, not a military one,'' Alvarez said. DAVID FINE

Convicted in a fatal bombing on the University of Wisconsin campus in 1970, when he was 18, Fine is trying to get permission to practice law in Portland, Orre.

Now 33, Fine spent six years as a fugitive and more than three years in prison for the bombing of the school's Army Mathematics Research Center, which killed researcher Robert Fassnacht. He passed the bar last fall, but a board of bar examiners has recommended he be denied permission to practice law on grounds of poor moral character. A formal hearing on his application is expected soon.

Two other persons indicted in the bombing, Karleton and Dwight Armstrong, served prison terms and were paroled. A fourth, Leo Burt, then 22, is still a fugitive. DANIEL BERRIGAN

A Jesuit priest, Berrigan, along with this younger brother, Philip, was one of the Catonsville 9, a group of antiwar Catholics who in May 1968 seized local draft board files in Catonsville, Md., and burned them with homemade napalm.

''We helped make people more thoughtful about what was happening,'' said Daniel Berrigan, who spent two years in prison after his Catonsville conviction.

Now 64, Berrigan lives in a Jesuit community house in New York City, where he works with the dying in a hospice program and regularly demonstrates against the nuclear arms buildup. He and his brother, who left the priesthood to marry a former nun and fellow activist, are appealing prison sentences for their parts in a 1980 antinuclear protest. J. WILLIAM FULBRIGHT

Chairman of the Senate Foreign Relations Committee when it was a major forum for dissent on the war, Fulbright, 80, calls Vietnam a great mistake and tragedy.

''I regret I didn't understand the situation earlier,'' he said. ''But no one at the time realized what it could lead to.''

The Arkansas Democrat spent 30 years in the Senate until his 1974 primary defeat. He says it took him ''a goodly while'' to reach the point at which he didn't believe his government. ''And now, I almost never believe it.''

Fulbright has been counsel to the Hogan & Hartson law firm here since 1977 and continues to write and make speeches, most of them critical of Reagan administration foreign policy. He helps oversee the Fulbright student exchange fellowships and cares for his ailing wife. Once in a great while, he says, he plays golf. ROBERT W. KOMER

Once called ''Blowtorch'' for his energy and upbeat reports to President Johnson on the war's progress, Komer was chief adviser to the pacification programs in Vietnam in 1967 and 1968. He later was a senior Pentagon official in the Carter administration and is now an unpaid consultant to the Rand Corp.

''With all the wisdom of 20-20 hindsight, I would have done a lot of things differently and been more cautious about getting us involved,'' he said.

An Alexandria resident, Komer, 63, calls the war ''a strategic disaster which cost us 57,000 lives and a half trillion dollars in today's dollars.'' In military terms, he adds, Vietnam took a hefty bite in the defense budget and sacrificed eight to 10 years of U.S. defense modernization. % GRAHAM MARTIN

The last U.S. ambassador to South Vietnam, Martin, 72, says it will take historians another 10 or 15 years to sort out what really happened there.

Martin blames the peace movement for forcing U.S. cuts in aid to South Vietnam, which he says assured defeat by the communists. ''I didn't think we should ever have been involved with sending troops at all,'' Martin said. ''But with just plain supplies and financial aid, you can do a hell of a lot.''

But when U.S. aid ceased, he said, ''Then the fighting stopped, and the killing began.''

Martin retired from the State Department in 1977 after a diplomatic career spanning 30 years. He lives in Winston-Salem, N.C., and his chief pastime now is ''watching my grandchildren grow.'' His personal papers, including top secret documents he took with him during the U.S. evacuatin of Saigon, are going to the National Archives.

''It will all be there,'' said Martin, who believes historians will judge ''that I was right all along.'' GLENN PONTIER

A pacifist from a family of pacifists, Pontier was drafted in the early 1970s to do alternative service but refused to cooperate. He spent 10 months in a federal prison.

''My intention was to live as a peaceful person, but it just so happened you couldn't do it at that time in this country,'' he said.

Pontier, 38, says going to jail ''changed my life.'' He lives with his wife and young son outside of Narrowsburg, N.Y., where he edits a small bimonthly newspaper and is comfortable being ''on the downward mobility track -- the opposite of a Yuppie.'' % HENRY E. (HANK) EMERSON

Known as ''Gunfighter'' and ''Wild Man of the Delta'' during his two Vietnam tours, retired general Hank Emerson, 59, served with the 101st Airborne and the 1st Brigade. He was wounded and severely burned in 1968 when his helicopter was shot down. Before retiring in 1977, he was commander of the XVIII Airborne Corps at Fort Bragg, N.C.

''American troops did beautifully under appalling circumstances,'' said Emerson, who is divorced and lives in Helena, Mont., where he spends most of his time hunting and fishing.

It galled him that his men would return from ''really kicking hell'' out of the Viet Cong and North Vietnamese ''and the next day, in comes the Stars and Stripes and you get some senator or someone making a speech or visitign Hanoi to protest the war.'' He is still angry that the war was fought ''with such ridiculous restraints . . . Somehow, bombing Hanoi was a big no-no.''

But what upsets him most is that ''the vets were treated like lepers.''

If any good came out of the war, Emerson says, it was that ''a lot of young guys got a whole lot of experience -- a hardening you can't get in peacetime training.'' He also thinks the United States learned through Vietnam that ''when you're there, you have to just get it over with . . . You can't vacillate. I hope it never happens to a generation of young Americans again.'' % JONATHAN F. LADD

Assigned to Vietnam as an adviser in 1962, Ladd returned in 1967 as commander of the Special Forces, the celebrated Green Berets. The ''biggest mistake'' of the war, he said, was sending in U.S. troops.

''Vietnam's problems were political, religious and ethnic and not the kind you resolve by American bullets,'' said Ladd, 64. He said as much while teaching at the Army War College, then ceased his critisms in 1965, when the first U.S. troops were committed ''and the muzzle was put on.''

Ladd retired from the Army in 1969 and later went to Cambodia for the State Department. He lives in the District and works for the Harris Corp., a high-tech electronics firm. DR. HOWARD LEVY

Defendant in one of the most widely publicized cases of the Vietnam era, Levy spent 26 months in a federal prison following his 1967 conviction for refusing to train Army medics bound for Vietnam.

''I don't have any regrets about it,'' said Levy, 48, now director of dermatology at Lincoln Medical Center in the South Bronx. ''I don't think the United States would have pulled out without the antiwar movement.''

Levy, who is divorced, lives in Brooklyn and shares custody of his 6-year-old son. He recently joined a local group concerned with Central America, and he says the Vietnam experience has helped arouse quicker public opposition to U.S. involvement there. COUNTRY JOE MC DONALD

The San Franciso singer/songwriter took his satirical antiwar sentiments and turned them into the ''Fixin' to Die Rag,'' a battle hymn of the Vietnam protest ear. The song, recorded by his group Country Joe and the Fish and a hit at the 1969 Woodstock festival, left a generation singing: ''And it's one, two, three, what are we fighting for? Don't ask me, I don't give a damn . . . next stop is Vietnam.''

''War is a losing situation for everyone,'' said McDonald, 43, who is about to release an album of songs about Vietnam and its aftermath. ''Everyone lost, and we will be dealing with it into the next century.''

McDonald served in the Navy before Vietnam and his antiwar work was tempered by his service in the military. He works with and does benefit concerts for veterans groups and says the whole country is suffering from post-traumatic-stress disorder. Married ''several'' times, McDonald has three children and runs Rag Baby Records out of Berkeley, Calif. He will tour here next month. Barry Sadler

A staff sergeant at Fort Sam Houston, Tex., in 1963, Sadler was drinking tequila and trying to please his Army buddies when he wrote and sang a tribute to the Special Forces. His ''Ballad of the Green Berets'l' -- Fighting soldiers from the sky. Fearless men who jump and die'' -- became their official song and an instant hit when it was released to the public in 1966.

But Sadler, wounded during his tour of duty in Viletnam in 1964, never had the same success with his other songs or subsequent books. He moved his wife and three kids to Arizona and sold batteries for a time. In 1978 he fatally shot a country music songwriter in Nashville and served 22 days of a suspended sentence for manslaughter. His former attorney says he has lost track of Sadler, 44, but hears one of his bookls may be made into a movie. BOBBY SEALE

These days the former chairman of the now-defunct Black Panther Party is trying to sell a video of his cookbook, ''Barbecuing With Bobby.''

He helps publicize a youth training program, attends Temple University, is thinking of running for city council in Philadelphia and wants to raise $10 million to $20 million to start a nonprofit foundation for community organizing.

Once bound and gagged in a courtroom for disruptive behavior during the Chicago Seven trial for conspiracy to incite riots at the Democratic convention in 1968, Seale, 48, recently signed papers so his oldest son, 17, could go into the service.

''But I talked him out of going into the Marines,'' he said, ''and I told him if he ever gets in a situation and doesn't want to fight to just call your daddy.'' WILLIAM L. CALLEY JR.

Convicted of murdering 22-unarmed civilians at My Lai and sentenced to life at hard labor in 1971, Calley, an army lieutenant, spent three years under house arrest of Fort Benning, Ga., then was paroled after the Supreme Court refused to review his conviction. Now 41, he lives in Columbus, Ga., where he is a salesman of V.V. Vick, his father in law's jewelry store. R. LAMONT JOHNSON

An infantryman during the Tet offensive, Johnson came back to his old job at the United Auto Workers in Washington and considers himself luckier than most returning black veterans.

''I'm probably one of the few blacks who just walked out of the fields and into a nice situation,'' said Johnson.

Still, he says he found the abrupt transition from the battlefield to the United States so jarring that he slept in his backyard, rather than an enclosed room, during his first few days home.

''Most of the blacks were drafted, without much education, and when they came back, they weren't able to work,'l' said johnson, 40, who watched one friend struggle for nearly two years to find a job.

The drug and alcohol use so common in Vietnam ''just stopped for me when I came back,'' Johnson said, but ''lingered on'' for others, particularly blacks who couldn'lt get into job training programs.

Johnson, who lives in Adelphi with his wife and young daughter, is now an EEOC officer at the Federal Highway Administration. He balks at assessing how he thinks the war affected the country, but he knows how it affected him:

''It was a terrible think being over there, watching friends die,'' he said. ''I would never go again, and if I was drafted, I would leave the country.'' ROBERT GARWOOD

As the only Vietnam-era POW found guilty of collaborating with the enemy, Garwood said he has had a tough time ''getting what's left of my life back together'' since his 1981 conviction.

He was a 19-year-old private first class jeep driver in the Marines, just a couple of weeks sky of going home, when he was captured on a beach outside Danang in 1965. Fourteen years later -- and six years after a U.S.-Vietnam peace agreement supposedly secured the release of all American prisoners -- he slipped a note to a Western economist in a Hanoi bar and soon was back in the States.

Former POWs testified that Garwood became a turncoat in captivity, interrogating and even guarding them and receiving preferential treatment. Garwood's attorneys said he had ''snapped'' in the face of incarceration, torture and starvation.

''I was just another casualty of the war,'' said Garwood, 39, who works in a Northern Virginia gasoline station and still believes the United States was right to get involved in Vietnam and wrong to leave. He is appealing his conviction, which cost him $150,000 in back pay, and is helping a congressional task force investigate the whereabouts of American soldiers he is sure are still alive in Vietnam.

''I was the last living American to come home'' he said. ''I was not the last living American in Vietnam.'' NGUYEN NGOC LOAN

His picture, taken as he fired a bullet point-blank into the head of a flinching, terrified prisoner during the 1968 Tet offensive, was flashed around the world. Today, the hand that held the pistol makes pizza in a suburban Virginia shopping mall.

''I have nothing to say,'' said Loan, 55, emerging from the kitchen of his Les Trois Continents restaurant in Burke -- pizza, subs and Vietnamese specialty dishes -- just long enough to politely decline an interview.

''That time,'' said South Vietnam's former national police chief, ''I hold to myself. I don't talk about it.''

Three months after the Pulitzer Prize-winning photograph was taken, Loan was severely wounded during a street battle on the outskirts of Saigon. He later lost a leg. Having survived attempts to deport him, Loan, the father of five, lives quietly with his wife and family. Two years ago he visited the Vietnam Veterans Memorial and pronounced it beautiful. ? DAVID MIXNER

With Sam Brown and others, Mixner helped found the Vietnam Moratorium Committee, which organized the largest peace demonstrations in the history of the nation in 1969 and 1970.

''I've always said there were two kinds of Vietnam veterans -- the ones who fought in the war and the ones who stayed home and fought,'' said Mixner, 38, who lives in Los Angeles.

Besides his work for numerous political candidates, Mixner became a gay rights activist several years ago. Recently, he left his own consulting company to be executive director of Pro-Peace, an international citizens movement that is planning a cross-country march next year to protest nuclear weapons. % KIM PHUC

Severly burned when her village was mistakenly pelted with napalm bombs in 1972, Phuc, then 9, became a haunting image of the war when she was photographed running naked and screaming down a road after the attack.

The photograph of the ''napalm girl'' won a Pulitzer Prize for the Vietnamese photographer. Phuc was hospitalized for 14 months. Last summer, suffering from headaches and painful napalm scars, Phuc, 21, was flown to a clinic near Heidelberg, West Germany, where skin grafts and other surgery relieved some of the pain and made it easier to move. Today she is a medical student at Ho Chi Minh University. % SARA FRANCES SHAY

While her son, Air Force Maj. Donald E. Shay Jr., remains missing in action, the war cannot be over for Shay and her family.

''He disappeared Oct. 8, 1970, and we don't know what happened,'' said Shay, 66, who lives with her husband, a retired college professor, in Linthicum, Md. Donald Shay, an Air Force Academy graduate, then 24, was flying photo reconnaissance in an unarmed plane.

Shay, whose daughter has since married and had two children, immersed herself in the National League of Families of American Prisoners and Missing in Southeast Asia. The group continues to push for ''an accounting'' of the 2,483 men still missing.

''We're not just a bunch of families expecting them all to march out of the jungle,'' said Shay, ''but we feel quite certain there are some people over there who are alive and continue to be held captive." % PATRICK TADINA

Considered the most decorated enlisted man of the war, Tadina was a staff sergeant with the 75th Ranger Company when he was credited with killing 111 enemy Vietnamese. In recognition of his valor, he received more than 25 medals, including two Silver Stars and eight Bronze Stars.

Tadina, 41, stayed in the Army and says he had no readjustment problems when he returned to the United States. His unit was among those that participated in the invasion of Grenada, and he later taught ROTC at Idaho State University in Pocatello.

''I did my job . . . I was a soldier, not a policy-maker,'' said Tadina, who is now sergeant major in a tank unit at an Army base in Schweinfurt, West Germany. ''The public cannot understand what it was like there.''