I really appreciated G. J. Meyer’s “A World Undone”. My [lack of] understanding of the conflict before reading that did not prepare me for how farcical and devastating the war was.

https://www.alibris.com/A-World-Undone-The-Story-of-the-Grea...

It’s a long, sometimes tough read (because of the contents, not the writing, which is very well done), but worth it.