For seven generations there had been nothing in the world more important than that wall. Like all walls it was ambiguous, two-faced. What was inside it and what was outside it depended upon which side of it you were on.

Clearly influenced by the Cold War being fought at its time of writing, Le Guin's exploration of politics, property, and revolution feels just as vital now as it must have done 40 years ago. This is the story of Urras, a typically corrupt late capitalist society, and its twin planet Anarres, home to exiled anarcho-communist revolutionaries. Le Guin weaves into the fate of these worlds a scientist attempting to unite two distinct theories of time (not unlike our current search for a unified field theory), and structures the book as separate but linked narratives taking place on each planet. The effect is to make us question the boundaries between things: between past and future, between politics, and between people.