The picture of hooded Klansmen riding to the rescue of an imperiled heroine and a ravaged South in The Birth of a Nation is an iconic image that is as mesmerizing as it is repellant. It did not appear so to the enraptured audience who cheered the horsemen along to the accompaniment of “The Ride of the Valkyries” played by a full orchestra when the film appeared in Boston in 1915 after previews in Los Angeles, New York, and the White House.

Eventually, it would be seen by millions of Americans. Not all of the viewers were enthralled by the spectacle. Boston’s black community rallied to seek a ban of the movie, protesting its blatant racism and falsification of history in what became a national dispute pitting civil rights against civil liberties. With the approach of the film’s centennial next year, Dick Lehr’s The Birth of a Nation: How a Legendary Filmmaker and a Crusading Editor Reignited America’s Civil War provides an engrossing chronicle of the struggle between racial equality and freedom of expression symbolized by two powerful personalities: black crusader Monroe Trotter and legendary director D.W. Griffith.

At first glance, no two men could be more dissimilar. Trotter’s father was an officer in a black Massachusetts regiment that had fought in the Civil War. Griffith’s father was a Kentucky colonel whose propensity for drink and debts left the family in straitened circumstances at his death when Griffith was 10. Trotter graduated magna cum laude from Harvard and became the first black man named to Phi Beta Kappa. Griffith embarked on a hardscrabble journey from farm boy to journeyman actor to vaudeville script writer to failed playwright to movie director grinding out hundreds of one-reelers for Biograph Pictures in New York during the first years of the 20th Century.

But what both men had in common was a streak of rugged individualism, stubbornness, and personal vision. Each could only function best running his own show. For Trotter, this meant becoming editor of The Guardian, a black activist newspaper in Boston and acting as leader of a dissident faction that challenged the quietist policies of Booker T. Washington, then the most powerful Negro in America.

Griffith, feeling constricted by Biograph’s formulaic one-reelers, set out for California where he eventually set up his own company, making lengthier, more sophisticated feature films that were no longer “movies” but “photo plays.” Griffith’s goal was to turn the fledgling picture industry into an art form. And his bid for glory was a costly three-hour, 12-reeler with innovative camera work, close-ups, and action scenes: The Birth of a Nation.

Trotter and Griffith both recognized the power of film as a mass medium that could influence millions. They would meet only once—in a Boston courtroom—but, in Lehr’s telling, they were on a collision course from the outset.

In November 1914, Trotter led a delegation to the White House to complain about segregation in federal jobs, which led to a heated exchange with Woodrow Wilson that the president considered insulting. Trotter denounced the administration policy before church congregations in Washington and Boston. Barely three months later, Griffith was invited to the White House where he conducted a personal screening of his new film for the president.

The director gained entrée to the White House through Thomas Dixon Jr., a friend of Wilson’s from the president’s college days, and the author of The Clansman, a novel whose staged version formed the basis of Birth of a Nation. Dixon was the most successful literary proponent of “Redemption,” which argued for the re-establishment of white supremacy in the South after the withdrawal of federal troops in the 1870’s. Its central idea was that after being humiliated by an insolent North which imposed the misrule of unfit blacks on a prostrate Confederacy, the South had risen to throw off the yoke of Reconstruction and restore order to a broken land. Dixon’s melodrama toured well but a movie afforded the play the opportunity of reaching a far greater audience.

By the time Griffith adapted The Clansman to the screen, Redemption was deemed a necessary corrective to the failed experiment of Reconstruction by the leading historians of the day, among whom was Wilson himself. America was then at the apogee of Jim Crow. The racist myths of Southern history had successfully been exported to the North. National unity had been achieved at the expense of the country’s black citizens. This rapprochement was The Birth of a Nation that Griffith evoked when he changed the name of his movie from The Clansman.

The film depicts a rose-colored version of the antebellum South—“a quaintly way that is to be no more’’—followed by the Civil War, the depredations of Reconstruction, and the inevitable retribution visited on the carpetbaggers and their Negro followers highlighted by the night-riders’ lynching of Gus, a renegade soldier (made up in black face) after a “trial” for attempting to defile a white woman who chose death before dishonor. The narrative follows two families, the Stonemans of the North and the Camerons of the South, each of whom will lose sons in the war, and whose surviving children will ultimately marry one another, symbolizing a reconciliation between both sections of the country.

The movie artfully incorporates all the precepts of Redemption: the defense of white womanhood from the lustful predation of the black man, the outrages of Reconstruction, the maladroit politics and social inroads of the newly freed Negroes. It manages to project all of the true evils of slavery and the Jim Crow South onto its actual victims: the master’s sexual use of slave women, the oppression and cruelty at the heart of slavery, the violence and intimidation that undermined Reconstruction.

It was in this atmosphere that the forces led by Griffith and Trotter clashed. Griffith reasoned that if his film could play in Boston, with its reputation for banning performances counter to public morals and its abolitionist heritage, it could play anywhere. Consequently, he launched a massive marketing campaign taking newspaper ads, offering interviews, soliciting libertarian support, getting cultural endorsements, lobbying politicians, offering selective previews, hiring lawyers and even recruiting detectives to spy on the efforts of his foes.

Trotter had fewer resources but he was playing on home turf. He rallied the black community to stage protests for the film’s sellout preview at Boston’s Tremont Theater, which caused a near-riot when blacks were prevented from purchasing tickets. In the ensuing melee Trotter was arrested. Outraged by its treatment, the black community was energized and turned out by the thousands to demonstrate against the film. A nascent NAACP was brought into the battle that had galvanized the city’s blacks.

The issue went first to Boston’s fabled mayor James Michael Curley. Although indicating his concerns with the film, the mayor said that since the issue went beyond conventional morality, his hands were tied and he needed the imprimatur of the courts or more stringent legislation to go any further. This set off a court battle, followed by Trotter and his allies marching to the governor’s mansion to seek a ban on the film, followed by a dramatic struggle in the state house in which the legislature expanded a censorship law enabling the film’s opponents to return the controversy to a three-member panel led by Mayor Curley. The issue had become a national front-page story, which to Griffith’s delight helped sell tickets. Throughout the spring, the film had continued its sold-out run. NAACP leaders, who supported Trotter, faced the dilemma of suppressing freedom of expression or permitting a film which could only act as incitement to a nation already infused with racial bias.

By late spring, The Birth of a Nation had been seen by 100,000 people in Boston and Mayor Curley, who could count votes and had a long memory for what he considered slights by Trotter, ruled against banning the movie. It might also be inferred that, by Curley’s lights, the film might be offensive but it was not immoral. The film went on to play to packed houses in Boston through October.

Ironically, Trotter had succeeded in tightening a censorship bill but failed to stop the movie. It was a victory for artistic freedom but not necessarily a defeat for civil liberties, since the conflict had nurtured a young NAACP, which gained strength in the ensuing battles for civil rights in the coming century. As for Griffith, in an interview he gave in 1941 when he was virtually forgotten in Hollywood, he remarked that “because of the social progress which Negroes achieved” given the oppression they faced, “it is best that The Birth of a Nation in its present form be withheld from public exhibition.’’

Although aspects of this tale have been told before, in refracting it through the prism of these two towering figures, Lehr—a former investigative reporter for the Boston Globe—offers a compelling narrative about an episode in American history that bears lessons for our own time.