It's only two volumes at the moment (a third is due, eventually; hopefully within the next couple years), but Stephen Kotkin's Stalin books are really great. Ostensibly a three-volume biography of Stalin (vol. 1 is 1879-1929, vol. 2 is 1929-1941, vol. 3 should be 1941-1953), it is far more than that in scope, looking at the geopolitical realities of the region in that time frame. As such they are huge: the first volume comes in at around 740 pages, the second at over 900, and each has roughly 200 pages of notes and bibliography (in three-column print, which is to say microscopic and thus even more information than the page count suggests). I have found the books a great and informative read, and having read parts of Evans' trilogy (I own it but haven't gone around to fully reading it) find it somewhat comparable in scope, in that it is a definitive account of the topic.

Richard J Evans book “Lying About Hitler” is also a good novel and talks about the history of David Irving and his lying about Hitler, Nazis, and Dresden. It also goes in depth about his libel trial. This is a great book that explains why you shouldn’t trust Irving’s books at all or use them as a source.

There is also David Glantz novels that go in depth about the Russian front and clears up many myths that have been established on both sides. A good start would be “Clash of Titans” as it goes into Operation Barbarossa. Though there are two versions of the novel: the original and revised edition. The revised edition just fills in some spots that Glantz missed as some of the archives were not opened yet as he wrote the original novel. But much of his sources are from the Russian archives.

I am partial to Bruce Catton’s Army of the Potomac trilogy.

It’s a narrative history of the Army of the Potomac (the Unions main/biggest army during the US civil war) during its many trials and tribulations before its ultimate triumph. It’s more of a popular history and was written in 1954, but it holds up pretty well and is absolutely beautifully written. He won a Pulitzer for the final volume.