I'd like some book recommendations on the collapse of the Soviet Union, particularly about the difficult process of becoming independent for the former SSRs. For example, how Ukraine dealt with its stockpile of nukes, the Transnistria situation, Georgia, Nagorno-Karabakh, etc. All of those things that have a lasting impact on geopolitics today.

I'd also like some book recommendations on the collapse of the Russian Empire and in particular how nationalist movements, for example in Ukraine, tried setting up their own independent nations, and how they eventually fell back under Russian control.

Any recommendations on topics along those lines would be appreciated!