Reddit reviews Doctor Zhivago (Vintage International)

Well of course the first place to start would be Wikipedia. You could look up:

1936 Soviet Constitution, Gosplan, five year plans, collectivization, kolkhoz, Gulags, the Virgin Lands campaign, TASS, Izvestia, Pravda, Elektronika, their incredible space program, etc. And of course the leaders. And the various republics (SSRs) would be good to know. In fact the country itself was CCCP = SSSR.

Read about all the post-collapse conflicts: Nagorno-Karabakh, South Ossetia, Chechnya, Transnistria, Russia-Georgia war, Ukraine Crisis. And about how turbulent the 90s were.

There are personal accounts of the gigantic conflict with the Germans, like those of Vasili Grossman and Marshal Zhukov. There are transcripts of interviews with Khrushchev and the books that Gorbachev wrote on Glasnost and Perestroika. Historian David M. Glantz writes almost exclusively about the Soviet military. There are the accounts of dissidents like Alexander Solzhenitsyn and Andrei Sakharov.

There are some classic pieces of literature like Master and Margarita and Dr. Zhivago. And music on YouTube by people like Shostakovich.

There are surplus stores like Soviet-Power.com that sell helmets, medals, coins, busts, and the like if that is what you are into. And blogs like English Russia.

r/history here on reddit probably has some articles to peruse. r/HistoryPorn often has old Russian photos.

And of course I've talked to several people on this forum who lived during Soviet times. I'm sure some here or elsewhere on reddit would be happy to tell you.