I thought this would be more fun than just listing the books I have hard copies of, so if anything strikes your curiosity, or you can't read the title, ask away. I have read all or big parts of around 2/3 of the stuff there, some I have more for just reference. I have way more stuff on pdf but this is more fun to share. Also yes in advance, I do give too much money to Verso.
I would highly recommend the soviet century by Lewin that I have in there for an overview of the period. The Sam Farber book on soviet democracy is also still really good. There's also J Arch Getty's work on the purges and Stalin period more generally. There was also a new book published this year on Stalin that I've heard great things about and will probably buy, Stalin: Passage to Revolution. I've heard the Stalinism to Eurocommunism book is interesting, but I haven't read it.
The Cold War and American Science so far is great. It's an academic history book, focused on the relations between MIT and Stanford and the Military Industrial Complex. It is dry in places as it goes over every single engineering lab that existed, but it gives some really good insights into how the whole machine really worked, and the psychology of the people doing that science, and those opposed to doing it. I'm also reading The Closed World by Edwards, which is a similar book but more broadly focused on reinterpreting the history of computers and cybernetics.