Designer on BGG is N/A, but actually the name is clearly printed both on the cover of the book and inside the cover at the copyright page:
Colonel Charles B. Richardson
I tried to google to see if he was known for anything else. The only thing I noticed that seemed like it was likely to be the same person was this book from 1863 also by Charles B. Richardson:
Southern History of The war: Official Reports of Battles
"As published by order of the confederate congress in Richmond"
"Confederate States of America War Dept"
So he was... the official historian of the CSA then, I guess...?
But it was printed in New York it seems, so I guess it was not completed until after the war was over?