This is the story of African-Americans employed by the National Security Agency, and its forerunners at Arlington Hall Station, from 1939 to 1956. It is, in part, an organizational history, since for most of that period, the overwhelming majority of African-Americans were segregated in primarily support elements, consistent with army policies and U.S. mores. It is also, in part, a cryptologic history, since technology and intelligence requirements factored enormously into African-American hiring and manpower utilization. For these aspects of the book, documents held in the NSA Archives as well as in the National Archives and Records Administration yielded a wealth of information.

But at its essence this book is about people who during WWII and the first decade of the Cold War were limited primarily to positions in the federal agency akin to those held in the private sector – critical, but low-paying, support jobs. Extensive oral interviews of both blacks and whites who worked there during the period added the human dimension to the research data and revealed the tremendous gulf between America's promise of equality and the reality, even within the federal bureaucracy.

The exhaustive interviews conducted for this book also include testimonies to the changes that occurred within the Agency, reflective of progress after President Truman's February 1948 message to Congress on civil rights and the issuance of Executive Order 9981 later that year which mandated the integration of the armed services. The book closes in 1956 as NSA is reorganizing and relocating to Fort Meade, Maryland. As part of the reorganization, a large, predominantly black organization, one of the most visible symbols of racial division within the Agency, was dismantled. Thus ended a major chapter in the Agency's social history, but for years afterward, issues of fairness and equality would continue to be at the forefront of the consciousness of many African-Americans at the National Security Agency.