In other countries, such as Poland and the Baltic states, it looked different: one occupation gave way to another.
The promised communist nirvana brought a mixture of mass murder, lies and latterly the grey reality of self-interested rule by authoritarian bureaucrats. Communist regimes proved remarkably durable, partly thanks to the use of privileges for the docile and intimidation of the independent-minded.
Readers over the age of 40 will find it an uncomfortable reminder of a dangerous and dismal past.
For most younger readers, it will seem all but unimaginable.
The communist block also had two bits of good fortune.
The economic slump of the 1930s discredited democracy and capitalism.
Lenin thought 1917 was too early for revolution in Russia.
At the Battle of Stalingrad, 50,000 Soviet citizens, including turncoats, volunteers and conscripts, were fighting on the German side.
Another source of strength was tight control of language and information that deemed most criticism unpatriotic.
Cracks came as information spread, especially about the system's bogus history and economic failings.