Steven V. Roberts, who teaches politics and journalism at George Washington University, roots for the Maret Frogs, where three of his grandsons attend high school.

Almost everyone knows Jackie Robinson, who integrated Major League Baseball in 1947. Almost no one knows Earl Lloyd. But they should.

When he was growing up in Alexandria, Va., in the 1940s with a father who worked in a coal yard and a mother who cleaned houses, young Earl often “walked across the 14th Street Bridge to play pick-up ball in the District,” writes John McNamara in “The Capital of Basketball: A History of DC Area High School Hoops.” After starring at Parker-Gray, a segregated high school, Lloyd became a two-time all-American at West Virginia State. But since pro basketball was closed to black players, he was headed for a career in teaching and coaching.

Then in 1950, the world changed. The Boston Celtics of the NBA drafted a black player named Chuck Cooper from Duquesne University, and the New York Knicks signed Nat “Sweetwater” Clifton, a star with the Harlem Globetrotters. With the 100th pick in the draft, the Washington Capitols chose Earl Lloyd, but they started their season one day before the Celtics. So Lloyd, notes McNamara, “became a pioneer in his own right as the first black player to make his debut in the NBA.”

It’s entirely fitting that a local player took that first step. As Gary Williams, the Hall of Fame coach at the University of Maryland, asserts in his foreword to the book, McNamara “wanted to show that DC was and is the best high school basketball area in the country.” He writes “wanted” because the author was one of five employees of the Annapolis Capital Gazette killed by a gunman on June 28, 2018. McNamara’s wife, Andrea Chamblee, found this unfinished book in his files after his death, and she completed the work with the help of veteran D.C. sportswriter David Elfin.

McNamara’s fascination with high school basketball began when he was 14 and a student at St. John’s College High School. His father took him to see the Cadets play the Archbishop Carroll Lions, and as he recalls, “seeing the action up close, getting a real sense of the skill of the players on the floor — the way you can only at a high school game — got me hooked. I could hardly wait to go back.”

He was “addicted” to basketball, McNamara admits, and especially for readers who don’t share the author’s fixation, this book has some serious problems. Far too many passages recite who scored how many points in winning long-forgotten games. But it comes alive when it captures the culture of basketball, the social significance of the sport beyond the box scores. And as Lloyd’s story indicates, the most enduring and intriguing theme is race.

Before the Brown decision of 1954 officially integrated the area’s schools, McNamara notes, “high school sports such as golf, tennis, swimming, and football were all still played in supervised, carefully curated grounds.” But basketball was different: “Integration had already occurred within the city’s boundaries — on the playgrounds.” Those playgrounds were “all-white during the week. But all bets were off during the weekends, when many facilities had no one on duty to enforce the rules. Consequently, blacks and whites willingly played basketball with and against each other, making young basketball players far less hung up on race than the rest of the city was.”

Eventually integration came to the high school courts as well, and one of the first mixed-race powerhouses was Archbishop Carroll, which won 66 games from 1958 through 1960 and lost only two. Photos from the Carroll yearbook show completely integrated squads that included a very tall young African American in the back row named John Thompson. Another star was Edward “Monk” Malloy, who later became a Catholic priest and the president of Notre Dame. “One of the qualities that made our team so noteworthy,” Malloy recalled, “was that we were a successful model of integration in a city struggling against its southern heritage.”

Thompson later played for Providence College and the Boston Celtics, but his greatest contribution to the game and to this city was as a coach. His first job was at St. Anthony’s, a high school that no longer exists, and long before he won a national championship at Georgetown in 1984, Thompson was embodying another theme of this book: the vital contribution high school coaches make to the development of their players, off the court as well as on. Dane Edley, one of Thompson’s proteges at St. Anthony’s, made a point repeated by many players about many coaches: “He gave us lessons that would help you later in life — things that carried over, like work habits. I didn’t understand it then, but I understand it now. He was trying to instill some values in you.”

A central figure in this book is Morgan Wootten, the legendary coach at DeMatha Catholic High School in Hyattsville, Md., who won 1,274 games before retiring in 2002 — the second-highest win total in U.S. high school history. Like Thompson, his biggest impact was on the individual lives of the youngsters he encountered. In 1980 he turned down the coaching job at North Carolina State and explained: “Any time I help a student in one of my classes, get a better start in his formative years, or touch the life of one of my basketball players, I feel I have climbed another mountain. That’s the kind I prefer climbing.”

So remember Earl Lloyd. He climbed his own mountain. Long before he integrated the NBA, he and countless other young African Americans integrated the playgrounds of this city and struck a small, bright spark for civil rights and social justice.

The Capital of Basketball

A History of DC Area High School Hoops

By John McNamara

Georgetown. 318 pp. $29.95