(CNN)On the court, Boston Celtics legend Bob Cousy was known for his "unshatterable poise." When he led his team's famed fast-break, he handled the ball with such ease that one observer said it "seemed to have wings and a homing device."
What white players owe their black teammates: Boston Celtics legend's tears offer an answer
But there was one basketball moment where Cousy lost all sense of control. He couldn't talk. He choked back sobs. He covered his face with his outsized hands to mask his shame.
It came while he tried to explain his relationship with his legendary teammate, Bill Russell.
An ESPN crew was interviewing Cousy on camera about Russell when the conversation shifted to the racism Russell endured during the Celtics' heyday in the late 1950s and early '60s.
"We could've done more to ease his pain and make him feel more comfortable," Cousy told the interviewer. "I should've been much more sensitive to Russell's anguish in those days. We'd talk ..."
And that's when Cousy loses it. His face contorts in anguish, and he breaks down. The interviewer quickly moved on after Cousy regained his composure. But Gary M. Pomerantz, an author and historian, saw a replay of the 2001 film and wanted to know more. He gave Cousy a call.
The result of that conversation is "The Last Pass," a new book that examines the complex relationship between these two iconic athletes.
"It's rare in America for a 90-year-old white man to reconsider race and how it played out in his own life, but that's what Cousy is doing," Pomerantz said. "He's not gilding any lilies. He's pointing out his flaws and admitting to them."
Cousy, or "Cooz" as he is commonly known, said he never anticipated the torrent of guilt he experienced when ESPN asked him about the man he calls "Russ." But he wondered if he should have done more for Russell; after all, Cousy had been the captain of the Celtics and the symbol of the team in Boston.
"I had this in my subconscious, of not having done enough for Russ," he told CNN. "It had been repressed. Something had brought it out."
"The Last Pass" isn't just about the past. It raises a question about the present: What do white athletes owe black teammates they've befriended when those friends take a public stand against racism?
Cousy isn't the only white athlete to ask if he should have done more. And plenty of white athletes face that question today, as more black athletes use their public platforms to protest racial injustice.
Cousy says telling other white players what they should do is not his style. He said white athletes should follow their own conscience when a black teammate speaks out.
One of history's most iconic sports photographs captures the choice one white athlete made. It shows two African-American sprinters giving a black power salute from the victory stand at the 1968 Olympic games as the national anthem was played. The two men, Tommie Smith and John Carlos, are heroes today.
Few, however, know what happened to the white sprinter who stood on the victory box with them. His name was Peter Norman, and he decided to publicly support Smith and Carlos by wearing a button advocating racial justice. That gesture infuriated so many people in his native Australia that he had to abandon his track career. Carlos called him "a lone solider."
In many ways, Smith and Carlos were the Colin Kaepernicks of their day. The former NFL quarterback began protesting racism by taking a knee during the national anthem, all but ending his career. Since then, other black NFL players have followed his lead -- including one man who found his own "lone soldier."
Philadelphia Eagles safety Malcolm Jenkins had been raising his fist during the national anthem to protest racial injustice. Before one game, Chris Long, a white teammate, walked up to Jenkins as he protested and put his arm around his soldier.
"I'm just telling Malcolm, 'I am here for you,' and I think it's a good time for people who look like me to be here for people fighting for equality," Long explained later.
When asked about the NFL protests, Cousy said he likes the message but not the method.
"I would divorce myself from the venue or the brand" to make the same point, Cousy said.
"I agree with the cause; I don't agree with the venue they chose," Cousy said. "It brings everyone under the gun. I think they might have lost a lot of support from moderate whites that they would have enjoyed if they had chosen a different venue."
It would be a mistake, though, to think "The Last Pass" is full of tormented introspection. Much of the book is a rollicking look at the early days of NBA.
Pomerantz describes it as an era when "matronly women rushed onto the court between halves to swing their handbags at Celtics players'' when they were on the road, fistfights routinely erupted on the court among players and coaches, and the NBA was so broke that players subsisted on $5 a day in meal money.
Russell, who could not be reached for comment, dominates many sections of the book.
He was the prototype of the freakishly tall athletic men of today's NBA. He was also fiercely intelligent, skilled in verbal combat, a voracious reader and utterly uninterested in helping white people feel more comfortable around him.
When Russell joined the Celtics in 1956, it marked a turning point. The team had drafted Cousy six years earlier but had yet to win an NBA championship. Together, the pair led the Celtics to six titles over the next seven seasons.
Still, the largely white crowds and white sportswriters in Boston cheered louder and longer for Cousy in a way they never would for Russell, Pomerantz said.
"At the time, the Celtics were considered Cousy's team, not Russell's," Pomerantz said. "That was a lie, at least partially coated in racism."
That treatment didn't silence Russell. He raised his voice. He became an outspoken racial activist. He led civil rights marches, spoke out in the media, and eventually became the first black coach in the NBA.
His activism made him a target. He frequently endured racial taunts. One of Russell's worst moments came when vandals broke into his home, spray-painted racial slurs throughout it and defecated in his bed.
"It was a time when very few athletes were speaking out against social injustice, but Russell did," Pomerantz said. "When Martin Luther King Jr. delivered his 'I Have a Dream" speech, Russell was sitting on the front row. He was engaged. His voice was heard."
Cousy, however, wondered if he should have raised his voice on behalf of Russell.
He wasn't the lone soldier type of activist. He fought for racial progress in subtle ways. He mentored two African-American boys in the Big Brothers Big Sisters of America program. He wrote a story for a national magazine about black being beautiful in the NBA. When his two daughters happened to date black men in college, he and his wife, Missie, gave their blessings.
"I've never been a soapbox person," he told CNN. "I've always been a private person that's had to live his life in a public bubble. My style in those days was, try to be helpful and do it by example rather than getting up and screaming at the press."
One of the book's striking revelations is that two men so in sync on the court were so distant off of it. Pomerantz said the two never really hung out, never talked about their personal lives or politics. Cousy couldn't understand why Russell was friendly toward other Celtics, but not him.
Part of it, Cousy admitted, may have been his own personality. He said he was a "shy kid from the ghetto" when he was on the Celtics. Russell was also standoffish, he said, and his bitterness at his treatment was palpable at times.
"Russ was the angry black man frankly, and I don't blame him one bit," Cousy said.
Still, the two men were "more alike than they ever understood," Pomerantz writes:
"Both outsiders, they were self-analytical and murderously competitive. They moved through separate worlds off the court, but on the creaky parquet floor of the Boston Garden they were interlocking pieces."
Cousy grew up in a New York tenement during the Great Depression when the city was filled with soup lines. Though he doesn't recall seeing a black person until his senior year in high school, he had experiences that made him more sensitive to intolerance.