In the days of young rage, when radicalism was both romantic and ordinary, only a few people were truly revolutionaries. Cathy Wilkerson was one of them.

The daughter of a wealthy advertising man and a graduate of a proper New England prep school, Cathlyn Platt Wilkerson traveled the well-worn path of many children of the '60s, through civil rights movement and the antiwar protests.

But perhaps because she was angrier, tougher or more desperate, she went one step further and became a leader of the Weather Underground, a group of several dozen youths who advocated armed struggle to overthrow the U.S. government.

A half-dozen Weathermen have turned themselves in the past few years, but Wilkerson is the first to face homicide charges. Three of her friends were killed in an explosion in her father's fashionable Greenwich Village townhouse in 1970. Police said the basement was being used as a bomb factory.

Wilkerson, who fled the scene of the accident, has pleaded not guilty to charges of criminally negligent homicide. For years, she and other Weathermen were sought by the FBI in one of the most massive manhunts in history.

The story of Cathy Wilkerson, revolutionary, is a puzzle with many missing pieces. She has refused to speak to the press about why she surrendered or what she did during 10 years underground. At her arraignment, she read a two-page statement saying she would "continue to oppose the practices and principles of imperialism."

One who has spoken with Wilkerson recently said she has not rejected her Weatherman past. "You can believe armed struggle is the proper course and not want to do it yourself," the source said. "Times have changed. She started in '64. That's 16 years ago. You grow. You learn. You change."

One radical who stayed in touch with the Weathermen speculates Wilkerson "grew tired of leading a double life. That's a tremendous burden to carry for 10 years. I think she feels now she can still be politically effective above ground, whether she's in jail or on the street. She just didn't want the yoke of a police warrant on her back."

The years underground were turbulent. Osawatomie, a magazine that Wilkerson and others published briefly in 1975, said, "We are . . . a revolutionary organization of communist women and men . . . responsible for over 25 armed actions against the enemy. Eight of these were bombings directed against imperialist war and in support of the people of Indochina. This includes the attack on the Capitol in 1971, on the Pentagon in 1972 and on the state Department in 1975."

Like Wilkerson, most of the Weathermen were from privileged backgrounds. Kathy Boudin, who fled with Wilkerson from the burning townhouse and remains underground, is the daugther of the prominent civil rights lawyer, Leonard Boudin. William C. Ayers, another leader who is still in hiding, was the son of a president of Commonwealth Edison in Chicago.

"It used to be a joke in the movement that you can't get into Weathermen unless your parents are millionaires," said one of Wilkerson's former associates.

The second of three daughters of James Platt Wilkerson, Cathy Grew up in the placid suburbs of Connecticut and attended New Canaan Country School and Abbott Academy in Andover, Mass. Her parents divorced before she went to Swarthmore College, outside Philadelphia.

Years later, in a movie made by Emile De Antonio called "Underground," Wilkerson said, "Our revolutionary consciousness was a result of growing up in the age of the atom bomb, of growing up in the '60s. We are who we are because Malcolm X was around teaching, and Rap Brown . . . ."

In her college freshman year, 1962, she went to a picket line in front of a Cambridge, Md., Woolworth's and heard a civil rights leader speak. "That was the beginning of realizing that there was a struggle going on that had deep importance for everybody's life, including mine," she said in the movie.

In 1964, she added, "I remember distinctly the day that I walked down a hall at school and there was a poster o n the bulletin board. It was a leaflet that had been put out by a black community group in Chester [Pa.] that was fighting for integrating the schools. The word was around that people were going to be arrested and I remember standing and staring at that leaflet and knowing absolutely that this was the time when I had to make a decision. If I got arrested I knew what the consequences were. I knew in terms of everything I had been programmed to do for the rest of my life. One of the people arrested besides me was Kathy Boudin."

By 1966, Wilkerson was organizing against the Vietnam war as the regional Baltimore-Washington coordinator for the Students for a Democratic Society (SDS). Reporters who covered demonstrations here remember her as a commanding figure with penetrating eyes and a powerful, magnetic voice.She would frequently grab a bullhorn and shout exhortations to marchers. She was arrested at least once here, for occupying George Washington University's Sino-Soviet Institute in April 1969.

During those years, she lived in a commune at 1779 Lanier Pl. NW, and was friends with many of the radicals of the day, from Tom Hayden to Mark Rudd. Friends recall a young man who was in love with Wilkerson and followed her into the movement. But she had little time for personal life and the Weathermen adhered to a strict communal code in which monogamy was frowned upon and sexual freedom encouraged.

In a 1969 article in New Left Notes, Wilkerson wrote, "Within the movement it is crucial that men and women both begin to fight against the vestiges of bourgeois ideology within themselves, to break down existing forms of social relationships. Only by developing forms in which we can express love in nonexploitative and noncompetitive ways will men and women develop their full human and revolutionary potential for struggle."

One antiwar veteran remembers Wilkerson as militant and strongwilled, but also thoughtful.

Another, a former SDS member, is less charitable. "She was driven by guilt about being born white and privileged," he said. "Any doubts about radical theory were thought to be signs of weakness, so she would draw herself further and further into a fantasy world about the way the world works. You could never have an intellectual discussion with her. She was mainly a tactics and strategy person."

This source remembered Wilkerson as "always trying to steel herself, to harden herself, as if it was in conflict with her nature. She was always trying to be tough. It was not easy to develop a close personal relationship with her."

At a demonstration outside Western High School in late '67 or '68, he recalled, "some greasers started fighting with the demonstrators. People were pushing and shoving and punching. I said, 'This is terrible.' Cathy looked at me, surprised, and said, 'Oh, no, this is terrific. People are communicating.'"

Wilkerson was among several dozen SDA leaders who splintered off in June 1969 to form Weathermen, taking their name from a line in a Bob Dylan song, "You don't need a weatherman to tell which way the wind blows."

The Weathermen demanded total commitment to revolution, with an almost religious fanaticism. They believed that if they proved, through violent acts, that they were not wimpy middle-class intellectuals, but "guerrillas fighting behind enemy lines," working-class youths would rise and join them.

"But it didn't work out so hot," recalled one Weatherman later. "We talked about racism and imperialism and the greasers talked about motorcycles and girls." Weathermen carrying Red flags into working-class neighborhoods were beaten up.

Barely a year passed before the townhouse explosion made national headlines and forced the Weathermen, already under surveillance by the FBI, to go underground. Wilkerson was one of 13 indicted by a federal grand jury in Detroit in July 1970 on charges of setting up a terrorist underground.

The indictment charged Wilkerson with making dynamite bombs on the day of the townhouse explosion.

The federal charges have since been dropped. (The current charges were brought by the Manhattan district attorney.) "The feds have dirty hands and they know it," said one of Wilkerson's attorneys, Elizabeth Fink. "They are afraid of what might be disclosed."

The Justice Department is prosecuting several top FBI officials who allegedly authorized an extensive illegal spying campaign on the Weathermen and on their friends and relatives.

Underground, the Weathermen, numbering perhaps two or three dozen, began by setting up several largely autonomous cells and according to one radical who kept in touch, "they assimilated themselves into the middle-class even to the point of forging IDs and using credit cards with false names . . . They were not hiding out. They were walking the streets, driving cars . . . They cut their hair, took off their jeans and started wearing double-knit suits and dresses."

Another friend said that since the Weathermen "came from well-heeled middle-class families . . . they had high-level contacts above ground. When they went underground, they used above-ground friends -- you know, everything from 'Do you have a place for me to stay?' to 'Can you lend me a few dollars?'" Several held conventional above-ground jobs.

But the Weathermen spend as much time fighting among themselves as fighting the outside establishment. Revolutionary activity petered out after 1975, as they argued over feminism and "male supremacy," over whether to come above ground, or whether to limit violence to selected political targets without harming people or whether to venture into assassinations and kidnapings like the Red Brigade in Italy.

Some of the men reportedly felt the feminism was overbearing and bailed out, leaving a larger part of the leadership in the hands of the women, including Wilkerson, Boudin and Bernadine Dohrn. There were also arguments over whether the group was too rigid and elitist, or whether, as the "vanguard" of the coming revolution, it should be small, highly disciplined and exclusive.

All of these struggles must have taken their toll on Wilkerson Movimaker De Antonio, who spent two days with five Weathermen leaders in a house outside Los Angeles in 1975, remembers her as "a person of quiet intelligence. You thought more of Brook Farm than the Weather Underground. She was very intense and strong and extraordinarily attractive.

"If one were to say this person were accused of throwing bombs, I'd have laughed. Of course, I could be wrong."

In the slender, well-dressed, even demure figure of Cathy Wilkerson as she faced the judges in two court hearings last week and fended off dozens of reporters and television cameras, there was little to suggest a revolutionary. Her mother and sister have come stay with her in New York and a bevy of lawyers is advising her.

Her statement, defiant by establishment standards, was mild in comparison with usual Weathermen rhetoric -- no references to "armed struggle" -- a concession perhaps to the belief that fighting words might not help her defense.

Attacking the FBI, the CIA, the police and the courts for "waging bitter battles" against Puerto Rican revolutionaries, blacks, native American radicals and Caribbean countries, Wilkerson said social conditions have not improved. "I have the same commitment to struggle . . . It is 1980, but the conditions still exist which caused colonized peoples to fight for liberation . . ."

But there was a hint of humility and a suggestion that a rejection of Weathermen machismo may have been what led her out from underground. "We've made many mistakes," she said. "Male supremacy undermined us, our arrogance led us to act as white supremacists even while we denounced it. However, national liberation struggles continue to teach us and inspire us and we must change and move forward . . .

"Women's liberation has challenged the legitimacy of physical brutality, exploitation and oppression in all spheres of life."

In the end, Cathy Wilkerson was still struggling with the irony of being a well-bred revolutionary. "I am here today and able to talk to you because I am white, middle class and free on bail," she told reporters. "Others who are black and brown do not get this opportunity and therefore it is my responsibility to say these things. In the end, I must be judged by how I act and what I do during this, the next stage of my life."