When Peter Jan Honigsberg went to the South as a 21-year-old law student to get involved in the civil rights movement, he was an "intense young man" who was "caught up in the thrill of the adventure."

But it wasn't until some 35 years later, after the University of San Francisco law professor and Berkeley resident finished his memoir, "Crossing Border Street," that he figured out his true motivation: He was repaying a favor.

Honigsberg's parents were from Kischlag, a small town in Austria, and after marrying, they moved to Vienna. They had applied for a visa to immigrate to the United States, and were still waiting when Kristallnacht took place.

A Catholic woman hid Honigsberg's father, and when the Nazis came to her door in search of Jews, she yelled at them for suggesting she had the audacity to hide a Jew. They believed her and left.

His father then received repeated letters requesting that he report to the train station. After he received the third warning that if he did not show up the very next day, the authorities would pursue him, the Honigsbergs received word that an American Jewish couple had agreed to sponsor them. They were among the last Jews to leave Austria.

"It always disturbed me that people had risked their own lives for my parents, and they never wanted to talk about it," he said.

Honigsberg grew up in the German and Austrian Jewish community in upper Manhattan's Washington Heights section. Henry Kissinger had lived in the same building as a teenager, and later, Honigsberg remembered anti-Vietnam protesters standing outside their building when Kissinger came to visit his parents.

Honigsberg's parents were hoping he would lead a normal, professional life as a lawyer at a reputable firm. Instead, he used his legal training to advocate for civil rights and join protests.

While in law school, Honigsberg decided to spend his summer in the South, providing legal representation for civil rights workers. After a brief orientation in Mississippi, he was assigned to a lawyer's office in Bobolusa, La.

Coming from New York, Honigsberg didn't think it was odd that so many of his fellow civil rights workers who were white also happened to be Jewish.

"Because I grew up in New York, where everybody was Jewish, I thought it was like that everywhere," he said. "I had a skewed vision, a real New York attitude."

Although he found the work fulfilling, Honigsberg was not content to just sit behind a desk and write legal briefs. It was 1966, and blacks as well as some whites were challenging the segregation laws in restaurants, beaches and other places.

"My supervisor, who was a Jewish lawyer from New York, was furious at me because he said I had no business as a law student getting involved in demonstrations," Honigsberg said. "My job was to get people out of jail, not go to jail with them."

But Honisgberg was determined. He thought that his clients would trust him more if he demonstrated alongside them, and he also didn't want to be labeled a "bystander."

So Honigsberg figured what his supervisor didn't know wouldn't hurt him.

In one incident, he went with Charles Simms, a black leader of a grassroots movement called the Deacons for Defense and Justice, Simms' wife and a white friend to desegregate a beach. On the way, they stopped at a gas station, where the white teenager who worked there refused to serve a mixed group.

They got out of the car and Simms motioned for the boy to come over. When Simms opened the trunk, Honigsberg could see "rifles, machine guns and grenades."

As Simms was an alcoholic and prone to having outbursts of anger, Honigsberg feared the worst; he thought Simms might do something crazy, like hurl a grenade into the gas station.

"I thought my life was over," he said.

The station attendant looked over the weapons, and hastily filled up the car with gas. They drove away.

"I saw the power of the gun and how this white kid wouldn't have served us if we wouldn't have threatened him," he said.

In his memoir, Honigsberg goes into greater detail about the Deacons, one of the few black power movements to actively fight the Ku Klux Klan.

Honigsberg spent two summers in the South, plus eight weeks during the winter. But even while he was enrolled in law school, he spent the bulk of his time working on the cases of the civil rights workers.

"Physically, I wasn't in the South, but mentally I was," he said.

After graduating law school, Honigsberg made his way to California, to visit friends. He had never been before, but as soon as he arrived in Berkeley, he knew he was home. He called his parents and told them he was not coming back.

While he had managed to avoid being arrested in the South, here he was not as lucky. He got arrested at a demonstration against the Vietnam War in People's Park.

Honigsberg worked for the National Housing and Economic Development Law project for a few years, and wrote several self-help law books. He also worked at the Swallow, a co-operative restaurant at the University Art Museum in Berkeley.

Once he married and started a family, he decided to become a professor and he has been at the University of San Francisco for the past 15 years.

In the afterword of "Crossing Border Street," he writes: "I can say assuredly that the civil rights movement made a vital and enduring difference for those of us who participated in it. We were profoundly transformed by the experience. The movement gave our lives meaning."