Robert Elias is a professor of law and politics at the University of San Francisco. He is the author of the forthcoming book “At What Price Equality? The Heroic Court Battle and Mysterious Disappearance of Lloyd Gaines.”

Lloyd Gaines had just become a civil rights pioneer. Denied admission to the University of Missouri’s Law School in 1935 because he was African American, Gaines sued, without much hope of winning in Jim Crow America. Yet after the U.S. Supreme Court finally heard his case in 1938, the justices ruled that unless Missouri created a black law school overnight, it would have to admit Gaines to the all-white law school. This was astonishing news for a black boy born dirt-poor in rural Mississippi who had watched racism follow his family’s migration north to St. Louis.

In the spring of 1939 it appeared, remarkably, that Gaines would enter the Missouri Law School later that year as the first African American ever enrolled there. On the cold, rainy evening of March 19, Gaines told a housemate he was going to buy stamps. He went out . . . and was never seen again.

What happened to Lloyd Gaines? Did he vanish because he and his family were threatened? Was he bribed to abandon his plans? Was he overwhelmed by the pressures of fighting his case? Was he so traumatized that he committed suicide? Was he murdered by racists? Did he leave the country?

There is evidence for all these theories, but the case has never been solved, or even seriously investigated, despite occasional pleas to the FBI by the NAACP and others. Not only did this legal trailblazer vanish, but the extraordinary story of his life and groundbreaking efforts also have been largely overlooked.

During the Great Depression, African Americans were hit particularly hard. The United States was gripped by economic destitution and Jim Crow policies that reflected the nation’s apartheid system. Sanctioned by the Supreme Court’s 1896decision in Plessy v. Ferguson, blacks endured a renewed servitude where separate facilities rarely existed and certainly were not equal. Seeking relief, many African Americans in the South joined the Great Migration north. Many held out great hopes but also suffered great disappointments.

Plessy’s official segregation was eventually overruled by the 1954decision in Brown v. Board of Education. But that dramatic reversal was not imposed overnight. Rather, it was the result of a long-term legal strategy launched in the 1930s by the brilliant NAACP attorney Charles Houston and the attorney (and future Supreme Court justice) Thurgood Marshall. They sought to wear down segregation by making it too expensive to provide even the semblance of real equality. An initial step in that strategy, and the first crack in the “separate but equal” doctrine, was made possible by Gaines, an honors graduate of Lincoln University, in Jefferson City, Mo., who hoped to become a lawyer.

After barring Gaines from the whites-only University of Missouri Law School, the state offered to help cover Gaines’s cost of attending law school in another state. Gaines refused. His family hadn’t moved north and paid taxes that funded state institutions so he could be forced to study elsewhere, he reasoned. The NAACP argued that paying a black student to leave the state didn’t satisfy the “equal” in “separate but equal.” Surprisingly, a majority of the high court agreed and ordered Gaines admitted.

The story of Brown is well known. But it has overshadowed the pioneering cases and actors that were its indispensable precursors. Lloyd Gaines was essential to the legal strategy launched nearly two decades earlier that targeted higher education overall and legal education in particular.

And what about Gaines himself — his life, aspirations, courage and even doubts? The 2007 Emmett Till Unsolved Civil Rights Crime Act asked the FBI to investigate unsolved civil rights era crimes and held out hopes of justice for past victims of racial violence. Gaines’s historic role in defeating segregation has been largely ignored outside of legal and other specific circles. Is his fate also being overlooked? Or will authorities finally launch a serious investigation?

Gaines was one of many African Americans who took enormous risks with little or no recognition. His story illustrates the psychology and rewards but also the costs — in inciting hatred and violence — of fighting racism. The battle against Jim Crow has still not been won, which makes it critical that the full history of segregation and the Great Migration be told. Those stories are crucial for moving toward a more racially just America.

In pursuing his lonely court battle, Gaines courageously stepped forward, not only for himself but also for countless others to follow. Yet his life ended in obscurity when he vanished into the night. Next week, 74 years will have passed since Gaines disappeared. What happened to Lloyd Gaines is a mystery worth resolving. And in the meantime, his memory should be revived.