Mention “school desegregation” and Brown v. Board of Education is the thought that pops into most minds, yet the first step toward African-American and white students sharing a classroom was taken 104 years earlier in pre-Civil War Boston.

The true story of Sarah Roberts, an African-American 5-year-old, is the subject of a just-released children’s book, The First Step: How One Girl Put Segregation On Trial, by Massachusetts author Susan E. Goodman. It’s a remarkable tale with threads that stretch into the landmark Brown case, yet it’s a historical event few know — even in a city steeped in history.

“Isn’t it crazy?” Goodman says regarding Sarah’s relative anonymity. “It’s an unbelievable story. I was so shocked I didn’t know about it. I lived in Boston for decades and I didn’t know about it until I went on a Black Heritage Trail walking tour. I thought, How can I not know about this? Then I thought, How could everybody not know about this? I knew I was going to write about it, right then.”

Sarah’s story was relatively straightforward: In 1847, her parents enrolled her in the nearby Otis School in Boston, which was close to her home and far better equipped than the city’s lone school for African-Americans, which had no playground and one (yes, one) book.

“Sarah had to walk past five schools for white children to get to an inferior one for African-American kids,” Goodman says.

She attended the all-white Otis School until the school committee discovered she was African-American and sent a police officer to remove her from class. Sarah’s parents — father Benjamin, a printer, and mother Adeline — sued the city to allow Sarah to attend a school close to her home, in what became 1850’s Roberts v. City of Boston. The family’s lawyers were noted abolitionist Charles Sumner (who would go on to represent Massachusetts as a Senator and nearly get beaten to death on the Senate floor for his anti-slavery views) and Robert Morris, the second African-American lawyer in the United States.

The family’s case made it all the way to the Massachusetts Supreme Judicial Court, where the judge ruled for the city after months of deliberation. While the Roberts family didn’t win the day, they certainly paved the way. In 1855, Boston became the first city in the U.S. to ban segregated schools.

Goodman astutely conveys all of these complicated themes for young minds across just 32 pages, in conjunction with masterful watercolor work by illustrator E.B. Lewis. These are big issues for little readers, yet she says Sarah’s story remains relevant today.

“It’s a story of what life was really like for one little girl in very different times, and yet it’s a struggle that is still going on for many people in our country, for many young kids in our country now,” she notes. “People think that history was so long ago, but those were people just like us. They had dreams, they had disappointments, they lived real lives, and I think that’s an important thing for everybody to realize.”

Goodman spent months researching the book, a quasi-mystery/adventure in itself that led her to the state archives, where she could read the original trial notes, to the heart of the then Big Dig, where a hard hat-wearing supervisor helped her figure out where Sarah’s house would have stood as they examined a 19th-century map.

“He said, ‘Lady, as far as I can tell, she lived right in the middle of the TD Garden,’” Goodman laughs. The one-book school for African-American children that was Sarah’s lone public option, the Abiel Smith School on Beacon Hill, still stands today. It is part of the Museum of African American History (maah.org) and offers exhibits and a step back in time.

“There’s something really wonderful about being a nonfiction writer who has to research a story and have it be your hometown,” Goodman says. “And to have that hometown be Boston, where there are so many great libraries, collections, and archives. I found old maps and tried to trace the walk she would have taken [to the Smith School]. I looked at paintings to try to get a sense of the hairstyles for E.B. I talked to so many experts. Did they have a cloakroom at this school or did they have coat hooks? You just keep plowing along until somebody can give you answers.”

Goodman even found one Roberts descendent, who shared family history. Benjamin Roberts was a printer who wrote for The Liberator, a newspaper for abolitionists. He came from a middle class family of activists, his father also active in the drive for equality.

Benjamin Roberts’s great-grandfather, James Easton, was a Revolutionary War veteran who refused to be seated in a segregated gallery in his Bridgewater church, so he bought a pew in the white section. The family was persecuted, so he bought a pew in the Baptist Church in Stoughton Corner. Fellow churchgoers tarred the pew, so the following week the family brought their own chairs into the pew. The pew was pulled down, yet, unbowed, they returned and simply sat in the aisles.

“Benjamin Roberts came by it honestly — his fervor for the cause — and had experience in it,” Goodman says. “For me, one thing that is really important about this story is change takes time. That’s one of the messages [that] was really important to get across — not to be patient, necessarily, but that we should recognize that sometimes even if you lose something there’s a victory involved in it.”

That victory would arrive nationwide in 1954 via Brown v. Board of Education, a case that has one amazing tie to Sarah Roberts’s fight 100 years earlier. In 1950, 8-year-old Linda Brown had to cross a train yard in Topeka, Kansas, walk six blocks, and then take a bus to her African-American elementary school. A better, closer school was just seven blocks from her home, but it was for white children only. It was the Sumner School…named after Charles Sumner.

“You don’t know how many times I checked that because I thought, There’s gotta be another Sumner. This couldn’t be right. But it was,” Goodman says.

While race and justice are still roiling issues in the United States, Goodman hopes sharing the story of Sarah Roberts will help counterbalance one of the grimmest periods in Boston’s rich history.

“I moved to Boston when busing was happening. One of the reasons I was so happy to write this book is those were very dark times,” she says. “And when people think of Boston and the word ‘desegregation,’ they think of a very, very dark time in the city’s history. I think that there’s been some strides, but it’s really complicated, as always. I think there’s something wonderful about our city, the fact we have another really important episode in the history of desegregation we can point back to with pride and celebrate, and that can be part of our history as well.”

Goodman offers a host of resources for families at the book’s Website: thefirststepbook.net. One feature is an anonymous survey for kids about race, one she created in conjunction with education research experts, professors who specialized in psychology, education, race issues and Africana studies, elementary school teachers, and principals.

“I’m hoping it might make families talk more about their own feelings, thoughts, and experiences,” she says, promising to share the tabulated results in the future.

Families can also visit the Museum of African American History on Beacon Hill (maah.org) and take the Black Heritage Trail walking tour that first inspired Goodman. The guided tour is seasonal, but resources for a self-guided tour can be found at maah.org/trail.htm. For older readers who want to learn more about the case, one other book has been written — 2006’s Sarah’s Long Walk: The Free Blacks of Boston and How Their Struggle for Equality Changed America by Stephen and Paul Kendrick.