Mercedes Rivera is one proud abuelita.

She just might be the proudest grandmother The Bronx has ever known.

For decades, Rivera's north Bronx apartment often doubled as a classroom for children who passed through her door. She spoke of baseball, her beloved island of Puerto Rico and all things New York.

All things.

She talked about her love for the Yankees and the Mets. She spoke of Harlem and Spanish Harlem. She believed there was no difference between light-skinned Latinos and dark-skinned Latinos because we were all Latinos, she said, and everybody had a story to tell. Some just told their stories in English while others told theirs in Spanish.

She reserved Tuesdays for watching Yankees games on WPIX Channel 11 with her grandson, Adrian, who was known back then as "Puchi". Young Puchi was a curious boy. He loved the sport but had no interest in stats. He loved baseball history and he admired players like John Candelaria, not because of his play on the field but because he was born in New York to Puerto Rican parents -- just like Puchi was.

While other kids played outside, Puchi would often stare out of his grandmother's corner window onto the nearby Woodlawn Cemetery and wonder about the lives of the famous men and women buried there.

In a plot within eyeshot of Rivera's window rested Negro Leagues legend Alex Pompez.

Years later, Puchi would get to know Pompez's story well.

Young Puchi is now Dr. Adrian Burgos, a professor of history at the University of Illinois, and his second book, "Cuban Star," tells the story of Pompez's complicated life as a U.S.-born Latino, numbers king, Negro Leagues owner and eventual member of the National Baseball Hall of Fame.

It's another story Burgos believes he was born to share. Burgos also authored the book "Playing America's Game: Baseball, Latinos and the Color Line" in 2007.

"The fact that Latinos in baseball are sometimes buried really deep behind layers and layers of sediment and history is what inspired me to write Pompez's story," said Burgos, a former college baseball player. "While researching 'Playing America's Game,' I found a lot of Latinos lived in black Harlem, and Pompez was one of them. He was really a Harlem story. It's really an American story of immigrants, the children immigrants and the possibilities that evolve for first- and second-generation Americans."

"Cuban Star" tells the story of Pompez, who was the son of Cuban immigrants, and how he navigated through baseball's color line and the racial integration of the sport. Born in 1890 in Florida, Pompez owned the Cuban Stars and the New York Cuban Giants in the Negro Leagues, but he was also numbers king -- he ran an illegal lottery-type game in Harlem -- and later worked as a scout and advisor for the Giants of Major League Baseball. His efforts helped the Giants acquire Negro League stars Willie Mays and Monte Irvin. He was also instrumental in the signing of Willie McCovey, Orlando Cepeda and Juan Marichal.

"What is fascinating is that his contemporaries gave him more attention and respect than what historians have," Burgos said. "I think the reason why that happens is that most people don't know what to do with the black Latino, or what do to with a U.S.-born person of Cuban descent that is clearly not white. He was caught in the Jim Crow era in baseball and business."

Pompez is not without his dissenters. Some critics claim the baseball man preyed on the poor Latinos in Harlem and exploited them with his numbers game. Pompez's partnership with New York gangster Dutch Schultz is also a point of contention.

Burgos explores the relationship with Schultz in "Cuban Star."

"His association with Dutch Schultz was about exploitation of race by a white gangster," Burgos said. "Schultz was able to crowd in on the numbers scene and use money to pay off police and judges and politicians so he could operate with reckless abandon. Remember, Schultz went after Pompez, and part of the reason he didn't kill him, in my opinion, is that he needed him too much because of his relationships. To penalize Pompez for two years of a hostile takeover by a brutal gangster who blasted his way into Harlem is unfair."

The criticism re-surfaced in 2006 when Pompez was among 17 Negro League members elected to the National Baseball Hall of Fame by a special committee, which included Burgos, while longtime baseball ambassador Buck O'Neil was not. The Hall of Fame eventually created the Buck O'Neil Lifetime Achievement Award two years later.

"Many teams in the Negro Leagues were dependent on numbers money," Burgos said. "It's about race and opportunity there. You have to understand the 1930s for what it was. The biggest issue that constantly confronted the Negro Leagues was capital. That's where numbers came in. If Buck O'Neil gets into in that election, I think much of that criticism of Pompez would have been muted. I wouldn't label Pompez a gangster. A numbers king, yes, but a gangster is a bit different."

Burgos did not escape criticism. Not long after the 2006 Hall of Fame announcement, Burgos and the other members of the Hall of Fame special committee were named "The Worst Person in the World" by Keith Olbermann on MSNBC's "Countdown."

That didn't faze Burgos. He believed sharing Pompez's legacy with the baseball world was the right thing to do then, and it still is now.

"My grandmother rooted for New York stories, and Puerto Rico, and Latinos to do well, and that's the type of fan I've become," he said. "I root for Latino storylines and I want to see them do well. For many of these guys, it is part of the American story and trying to make good."