The book makes one point clear. In the case of the State of Virginia, the bulk of the labor force to sustain the Confederate military needs was African American; and there was always a shortage of manpower either in the military and the labor forces to support the Confederate Department of War. So there was always a shortage of Whites to man the military and a shortage of Blacks to man the factories, boatyards, rail yards, hospitals, mines, engineering departments, farms, warehouses and all other services to support the military. It was a balancing act that eventually collapsed. There was no way to create a 100,000 man armed force made up of Confederate African Americans and at the same time keep the military machine going. No wonder it took the Confederate Government so long to finally act and authorize forming Black Confederate military units. What ever fighting African Americans did for the Confederacy it had to be on a very small scale compared to the White Confederates in combat. This was true for the North as well. By percentage, Black Union soldiers saw much less combat than their White counterparts. And if you compare the size of the military machine and army for the Union to that of the Confederate, it is miracle the South held out as long as it did. A testament to the determination and skill of the Confederate War Department , Army and Navy, and all those associated with that military machine.