This book tells the important story of Benjamin O Davis Sr and Jr, America’s first Black father and son generals. Triumphing over the harsh racism of the first half of the 20th century, their accomplishments were as important to the integration of the US armed forces as the achievements of men like Martin Luther King Jr and Bayard Rustin were in the civilian world. Their comparative anonymity is the reason the author Doug Melville called his book Invisible Generals.

After Davis Jr was named commander of the first all-Black air unit, the 99th Pursuit Squadron, and later of the 332nd Fighter Group, a larger all-Black unit, he led the celebrated Tuskegee Airmen, one of the most successful fighting units of the second world war.

Melville’s father was raised by Davis Jr, so the author was thrilled when he was invited to a gala screening of Red Tails, George Lucas’s movie about the Tuskegee Airmen in 2012. But he was horrified when he discovered the movie had changed his grandfather’s name from Davis to Bullard. That anger fueled Melville’s determination to bring new attention to his ancestors. A self-described “entrepreneurial thinker and marketer”, he is not an elegant writer, but his story is powerful enough to propel the reader all the way through.

After Davis Jr was admitted to West Point in 1932 – a privilege denied his father, who nevertheless became America’s first Black general – the younger Davis was completely ostracized by his white classmates, none of whom would speak to him, room with him or a share a table to eat. Nevertheless, Davis graduated 35th in a class of 276. Commissioned as a second lieutenant, he became only the second Black officer in the 20th century. His father was the first, commissioned in 1901.

The difficulty of achieving those commissions is suggested by a heinous internal report produced by the army in 1925, which said the American “Negro” had not developed leadership qualities because of “mental inferiority” and an “inherent weakness of character”.

Like every minority group that has fought to prove the truth of Declaration of Independence – that all men (and, much later, women) are created equal – Black people had to wildly outperform their white counterparts before their inherent talents would be recognized. The younger Gen Davis and the men under his command did that in the second world war.

In its obituary of the younger Davis, the New York Times noted the Tuskegee Airmen had an extraordinary record “against the Luftwaffe … they shot down 111 enemy planes and destroyed or damaged 273 on the ground at a cost of more than 70 pilots killed in action or missing. They never lost an American bomber to enemy fighters on their escort missions. As the leader of dozens of missions Gen Davis was highly decorated, receiving the Silver Star for a strafing run into Austria and the Distinguished Flying Cross for a bomber-escort mission to Munich.”

Almost every triumph of this father and son was tinged with disappointment because of virulent racism. When Davis Sr received a richly deserved promotion from Franklin D Roosevelt that made him the first Black US general, in 1940, the appointment was derided as an effort to appeal to the Black vote in New York and Illinois and “an appeasement” of the National Association for the Advancement of Colored People.

Six years later, Davis Sr was appointed by Harry Truman to the president’s committee on civil rights, to plan the integration of the armed forces. But instead of standing by Truman’s side two years later when the president signed the executive order which was one of the first great triumphs of the modern civil rights movement, Davis was nowhere to be seen – because he had been forced to retire just six days earlier. Similarly, when his son was eligible for his fourth star as a general, Lyndon Johnson inexplicably refused to approve the promotion.

The second half of Melville’s book records some of the ways America has made amends. Years after the younger Davis retired, at the urging of Senator John McCain, Bill Clinton finally bestowed his richly deserved fourth star. But the ageing general barely understood what was happening, because of the onset of Alzheimer’s.

Melville played a significant role in the lobbying effort that led to his grandfather’s greatest vindication. In a competition with William Westmoreland and Norman Schwarzkopf Jr, Benjamin Davis Jr finally won the respect from West Point he was denied in four years as a cadet. In 2017, less than one week after one of America’s worst racist events in Charlottesville, Virginia, Melville traveled to West Point for the dedication of the Gen Benjamin O Davis Jr Barracks, a brand new dormitory at the center of the campus.

Melville insisted that the construction men and women who worked on the dormitory be invited to the ceremony. One led him to at stone on which he had secretly etched a version of Psalm 118:22, 200ft from the entrance to the imposing new building. It read: “The stone which the builders rejected has become the cornerstone.”

• Invisible Generals is published in the US by Simon & Schuster