While I have not yet read the book, it probably has included most of whatever we may be able to post here as far as documentation regarding the service of soldiers of African-descent in the Confederacy.

However, I think it does serve a purpose to post it...that being to show that the premise of this book can be independently verified as backed by written source documentation. In that vein, I'll add this:

From "Tom Dooley, and Other Interesting Snippets From the Pages of ‘North Carolina Troops, 1861-1865’." by Terry Foenander.
REVELS, Henry and
REVELS, Jonathan
Both were privates in company F, 51st Regiment North Carolina Troops, and were probably brothers. Both are shown as being born in Robeson County and enlisting there on March 10, 1862, at ages 35 and 40, respectively. However, by July 1, of that year, both of them were discharged, the notation on their papers stating: "Discovered to be a Negro." [12, 338]
See http://home.coffeeonline.com.au/~tfoen/tomdooley.htm

The significance of this is that this shows that they *wanted* to serve in the Confederate Army, so much so that they attempted to hide their race!

And, here are some of interest from my own research:

O’NEAL, William Armistead’s/12th Miss. and Ala./12th Miss. Cav./16th Conf. Cav., Company Unknown (Born of African descent in Pickens County, Ala. in 1846. Listed on the “Tennessee Colored Pension Applications for CSA Service”, listed as a member of the 12th Miss. Cav. Regiment.)

[UNKNOWN LAST NAME],Wash, Personal servant of Capt. B.B. McCaa of the 8th Conf. Cav. (Probably of African descent. Responsible for taking care of the Captain’s horse, “Indian”. After Capt. McCaa’s death from wounds at Murfreesboro, Wash brought “Indian” back to Pickens Co.,Ala. He traveled at night, and hid during the day, to avoid the enemy. The McCaa family did not include Wash in the count of family owned slaves, so if he was of African descent, he may have been a freeman. Wash was married to a lady named Mary.) Source: McCaa family history...I believe this is at least partially from the book "Dr. John McCaa, Camden, S.C., His Descendents", by John McCaa.

COLEMAN, Jacob 11th Alabama Infantry Regiment, Company Unknown. (Of African descent. On roll of “Tennessee Colored Pension Applications for CSA Service”, listed as a member of the 11th Alabama Infantry Regiment. Born in Courtland, Lawrence Co., Ala. in 1839.)

MOORE, A.J.C., 40th Ala. Inf. Regt., Regimental Cook [thought to be voluntary] (Of African descent.) Source: I think that this is directly from the regimental microfilm.

A Confederate reunion was held in Birmingham, Ala. [I forget the year off the top of my head.] A photo of the participating veterans, which is still existing, shows fully one-half of the Confederate veterans attending were of African descent!