In the period in between the first and second parts, the Cold War ended with the peaceful merging of the Eastern and Western blocs into a single, planet-wide Soviet-ruled dictatorship, which hardly made any perceptible change, as the West's political system had already become virtually identical with the Soviet one. However, this dictatorial power was broken by the spindizzy drive which works for very large objects, so that dissidents and malcontents have an easy way of escaping and going off into space. First factories, then eventually whole cities migrate from the economically depressed Earth in search of work; these space-wandering cities are called Okies.