this is the latest and possibly last in a long series of alternate history novels that have shown us an america where the south won the civil war, and history has taken a different turn as a result.
This started with a book called how few remain that detailed a second civil war in the 1880's.
the following trilogy the great war showed us world war one in america with the north versus the south again.
the next trilogy american empire showed us this world from the 20's to the 30's with the south falling under control of a fascist leader.
and this book is the fourth volume in the series return engagement, which details a new war between the two in the 1940's.
It actually is very easy to read and you might be able to pick it up without having read the former volumes, but I would recommend going right back to the start of the series as you'll get more out of that way.
harry turtledove as usual writes prose which is not great literature but is very readable, and uses a fair few characters as his viewpoints, scenes shifting between each on regular occasions.
the war actually ends two hundred pages before the end of this six hundred and eight page book, and what the last two hundred pages cover is the aftermath. the war may have finished but all the hatreds haven't gone away. and like real wars, it doesn't end with a last minute attack on the villains base and everyone living happily ever after, it ends with peace treaties and people wondering what the future will hold. the writer doesnt shy away from depicting all the hatreds and it does make you think about the resulting moral issues, which is good writing.
I've followed these characters through a lot of books now, and if this is the end of the story I will be sorry to see them go. A good read.