Torn between two books I've only just ordered, I can get started immediately by reading online at archive.org David Remnick's "Lenin's Tomb - The Last Days of the Soviet Empire". I know I will struggle to read the whole 600 pages online, so perhaps I wait a little longer and meantime listen to David Remnick's commentary.
As for the other book, it's by the renowned Australian historian, Sheila Fitzpatrick, whose main subject is the history of the Soviet Union and history of modern Russia, especially the Stalin era and the Great Purges, which she's distilled in "The Shortest History of the Soviet Union". You can read a generous 50-page preview of the 250-page book here.
Let us all hope that by the time I have received the books in the mail and read them both, the war in Ukraine has been consigned to history.