On Sherman, see Victor Davis Hanson's book "The Soul of Battle: From Ancient Times to the Present Day, How Three Great Liberators Vanquished Tyranny," assuming you aren't too wedded to current propaganda to look at things in another way.
Civil War fanatics might appreciate the movie, "Ride with the Devil." Long, earnest and boring, but plenty of detail to discuss, and not overly biased in favor of one side or the other. It does have something epic in it. Turner's "Gettysburg" and "Andersonville" are also of interest.
But the magnitude of the application was. Mr. Sherman's modern view of warfare on the populace far exceeded that of anyone before him, much less an unauthorized outlaw like Quantrill.
Perhaps you would care to compare and contrast Sherman with Lee or Mosby, unless you are too steeped in Union rationalization history.
Remember that Mr. Lincoln was receiving descriptions from Sherman and doing nothing to stop the madman, because to do so would require negotiations between the two governments, and Mr. Lincoln was going to have it his way.
And thanks for your recommended reading, but we have our own, dating back to 1861.