The notes left little question for Henry Aaron.
They addressed him by racist terms rather than by name and explained how the country would be humiliated to have a black man as home run king. Some threatened physical harm to him and his family.
"All that hatred left a deep scar on me," Aaron wrote in his 1991 autobiography. "I was just a man doing something that God had given me the power to do, and I was living like an outcast in my own country."
The letters reminded Aaron, the Atlanta slugger who had grown up in the segregated South, that even if schools, voting booths and ball fields were open, a black man could not do something great without tapping that deep, old well of intolerance. In 1974, race still mattered in very apparent ways.
Now, 33 years after Aaron passed Babe Ruth, it's not so clear.
Tuesday night, another black superstar, Barry Bonds, hit his 756th career home run to break Aaron's record, to the chagrin of many baseball followers. But most cite allegations of steroid use and Bonds' standoffishness as the chief reasons. As promised, Aaron was not present at AT&T; Park in San Francisco to honor the new king, though Aaron did send a taped video message saluting Bonds' achievement, which was shown on the ballpark's big screen.
Those who automatically dismiss race as a factor in Bonds' lack of popularity, however, may want to consider several polls released this year.
Not only are black fans far more sympathetic to Bonds, these polls say, they are far more likely to believe race is a factor in the way he's perceived.
An ESPN/ABC News poll released in May indicated that 74 percent of black fans were rooting for Bonds to break the record compared to 28 percent of white fans. ESPN said the telephone poll was conducted among a random national sample of 799 adult baseball fans, including an oversample of 203 African-Americans.
A CBS News/New York Times poll released in July found that 62 percent of black fans believed race was at least a minor factor in the steroid suspicions around Bonds. Only 14 percent of white fans felt the same way.
That contrast in perceptions suggests that there are racial issues to be examined around the home run chase.
"It's one of those things that's just there," said Dave Zirin, a sports columnist and author who has written extensively about Bonds and race. "Whether you think race should be talked about in this story or not, it's there objectively. I don't know why we should be surprised. Race and sports have been our twin national obsessions for going on a century."
Zirin, who has written two books about Muhammad Ali, has talked about Bonds on mainstream sports radio (National Public Radio and ESPN) and on radio targeted more specifically to African-Americans. The tone couldn't contrast more, said Zirin, who is white.
Many mainstream sports fans abhor Bonds, the author said. But he has heard many African-American callers who expressed serious concerns for the slugger's well-being.
"They see this hatred toward him as the same thing that happened to Hank Aaron," Zirin said. "It feels the same to them. It feels like a double standard."
Zirin said he can't reconcile that contrast in tone without considering racism. He believes that if a white star with the same personality and same association with steroids had broken Aaron's record, fans would be ambivalent but less enraged than they are at Bonds.
Not so, said one Hall of Famer who witnessed Bonds' historic clout. Asked yesterday whether he thought negative reaction toward Bonds had anything to do with racism, former Orioles star Frank Robinson said: "Race has nothing to do with it. No, it just has nothing to do with it."
A canvas of fans at Baltimore's ESPN Zone ran the gamut. Devorick Little, 41, of Glen Burnie, said he wanted Bonds to break Aaron's record because "he's been playing for a long time and I think he deserves it. But I think race is a major factor in the way he's being perceived, in addition to being a factor in the entire steroids scandal," said Little, who is black.
Lou Mascola disagreed.
"I don't think race played any part" in the public's disdain for the Giants slugger, said Mascola, 55, a white man from Bristol, R.I. "He [Bonds] just always came off as arrogant."
Todd Boyd, who holds the Price Endowed Chair for the Study of Race and Popular Culture at the University of Southern California, recently wrote a column for ESPN.com about the racial issues around Bonds. Boyd, who is black, was surprised how angry some readers became at the suggestion race might play into fan backlash.
"Why are you inserting race?" Boyd said they would ask. "Well, I'm not inserting it. It's there. It's almost impossible to talk about the evolution of that record, from Ruth to Aaron to Bonds, without talking about race."
Jules Tygiel, a historian in San Francisco who has written about Jackie Robinson and the Negro leagues, isn't so sure.
"Race is always a factor, but, in this case, I think it's very minimal," said Tygiel, who is white. "On almost any issue, there will be a disparity between the way whites look at it and the way blacks look at it. But Barry is Barry, and he's spent a long time building ill will."
Tygiel is a Giants fan who counts watching Bonds as "one of the great thrills of my life."
He can't look at the reaction to Bonds and equate it with the racism Aaron experienced after what is often considered the end of the civil rights era. He cited negative public reaction to Rafael Palmeiro and Mark McGwire as proof that fans feel harshly toward many perceived steroid users.
"The hard part with Barry is that he's such a complex personality," Tygiel said. "He's such a difficult person to deal with that it's hard to portion out the factors behind reactions to him."
Other black stars have said Bonds is treated differently than a white equivalent would be.
"It's so obvious what's going on," Minnesota center fielder Torii Hunter told USA Today in April 2006. "He has never failed a drug test and said he never took steroids, but everybody keeps trying to disgrace him. How come nobody even talks about Mark McGwire anymore? Or [Rafael] Palmeiro [who tested positive for steroids in 2005]?
"Whenever I go home [to Pine Bluff, Ark.], I hear people say all of the time, 'Baseball just doesn't like black people. Here's the greatest hitter in the game, and they're scrutinizing him like crazy.' It's killing me because you know it's about race."
Those who see Bonds as a victim of racism wonder why white stars such as Roger Clemens and Lance Armstrong, who have also faced doping allegations but never failed drug tests, continue to be highly regarded.
"I think a lot of African-Americans wonder why Bonds has been singled out," Boyd said.
Blacks loved, hated
Bonds' father, Bobby, faced prejudice as a minor league star in the South and felt he was treated poorly during his major league career because he was an outspoken black man. Barry Bonds grew up in the comparatively gentle world of California's upper-middle-class suburbs but, as one of only a few blacks in his neighborhood and school, he faced racial isolation.
In his early years in Pittsburgh, Bonds complained, often correctly, that white stars such as Andy Van Slyke and Sid Bream received gentler treatment from fans and media than he or Bobby Bonilla. Years later, when asked if he might receive some of the same privileges as Clemens - like being able to skip road trips - the Giants star replied: "I ain't white. What world you living in? I live in reality. They'll never let a black man get away with that."
There's little question that black superstars have become more accepted by mainstream America.
First Michael Jordan and then Tiger Woods and LeBron James became marketing powerhouses on previously unimaginable scales.
Other black stars, from Derek Jeter in baseball to Tim Duncan in basketball, are considered examples of doing everything the right way.
Yet some believe that once black athletes get into legal trouble or reveal belligerent sides to the media, they are vilified more quickly than their white counterparts.
"The surly African-American athlete is still taboo and raises a lot of ire," Zirin said. "It's an interesting measure of how far we've come and how far we haven't come."
He sees powerful connections between Bonds and Jack Johnson, the early 20th-century heavyweight champion who shocked white audiences with his audacious style and unabashed pursuit of white women.
Joe Louis reversed that 20 years later by becoming a prototype for Jordan and Woods - brilliant in the ring, unlikely to buck social expectations outside it.
The nation's tendency to embrace the Louis type and feel uncomfortable with the Johnson type hasn't changed as much as some might wish.
"Black athletes are very visible, they make a lot of money, and a lot of people feel that the money should, in essence, shut them up," Boyd said. "
Tygiel said that may be true but said he would not equate Bonds with social crusaders such as Johnson, Jackie Robinson or Curt Flood. "Barry hasn't been outspoken on issues," he said. "I just don't think that explains the reaction to him."
Boyd agreed that Bonds is no activist. But that doesn't eliminate race as a factor in the feelings toward him, he added.
Boyd linked Bonds with Kobe Bryant in a group of second-generation black athletes who raise different questions for fans than the first wave of black superstars.
"He's a spoiled brat basically, and people don't know how to react to a black spoiled brat," Boyd said. "If he were an outspoken guy from a poor, urban area, at least people have more of a history of dealing with that. But there's no model in place for dealing with a guy like Barry."
Sun reporters Sirage Yassin and Dan Connolly contributed to this article.