Started off the year with a fun one, I did...
Wars are exhaustively covered in Western literature. No human being can read all of the books, even just in English, much less in other languages, that have been written about World War II, for example. That war is covered in many excellent volumes that cover the war as a whole, from a nice high overview, down to increasingly specific topics like the experience of individual German squads on the Eastern Front in 1943.
The point being, when it comes to wars, particular of the "modern" era, you can probably find at least one, if not many, books that speaks to whatever about that war you wish to know about in greater detail.
That is, unless what you're interested in is: What Happened After?
Fortunately, this genre has been picking up steam in recent years. For World War II, there's the excellent Savage Continent: Europe in the Aftermath of World War II by Keith Lowe, which tells the sad but necessary epic of the decade after VE Day, when an entire continent basically smashed to bits had to try and rebuild and also have a reckoning with what they had done to each other for a second time in a generation now. In the Ruins of Empire: The Japanese Surrender and the Battle for Postwar Asia by Ronald Spector does the same thing for the Pacific Theater. There have been many volumes rethinking the "Fall of Rome" and going into great detail regarding the century after 476CE in Europe.
And now, it's The Great War's turn.
The immediate postwar era of World War I is even more fascinating due to how those five or so years made the Second World War basically inevitable. And this is the ground The Vanquished covers.
From the "end" of what we refer to now as World War I in November of 1918 until about 1923, everything from the Rhine to the Pacific coast of Russian, from Finland south through the Balkans and into Mesopotamia, experience further violent conflict. Even the victors, with the sole exception of France, suffered additional violence and chaos (Britain with the Irish uprisings and Italy thoroughly enmeshed in the former Austro-Hungarian littoral on the Adriatic as well as suffering internal convulsions).
Gerwarth walks the reader through this tangled muddle as best he can, grouping events like revolutions, civil wars, interstate wars, irredentist conflicts, etc., together, in an admirable attempt to make sense of it all. To give an idea of the difficulty of the task, Wikipedia (not an authoritative resource but, again, to just give an idea) lists SEVENTY distinct violent conflicts in Europe from the end of 1918 through 1922.
The Vanquished tries to avoid descending into just an unending narrative of violence and cruelty, even though this is what the period was about, and instead tries to show the causes of the violence and the longer-reaching effects. I'm not personally certain that there was any result other than the breakup of the four empires that ended World War I and directly resulted in the chaos of the aftermath covered here that was possible, but Gerwarth makes a fairly convincing argument that it would have been difficult to fuck up the details and implementation of those breakups any worse than the Allies actually did.
Worse, the mismanagement of the "peace" contributed directly to the fall of democracies across this entire region and the resulting, even worse conflict of World War II. A lot of folks are aware of the correlation between the harsh Treaty of Versailles and its effect on the defeated Germans, but Gerwarth gives equal time to the equally harsh Treaties of Sevres and Trianon, each of which also carried great weight as contributing causes to World War II.
Trying to make sense of all of the horror that happened in the immediate half-decade following World War I is a tough task for any author, but Gerwarth manages it well here and this is a great one-volume overview of the entire period. If you wish to dig deeper into any specific aspect of it, I'll just mention here that, per my Kindle, the narrative ends at 60% of the book. The remaining 40% is just to cover all of the documents and other books referenced in said narrative. Yeesh.