The Dispossessed by Ursula Le Guin
'There was a wall. It did not look important - even a child could climb it. But the idea was real. 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...'
Shevek is brilliant scientist who is attempting to find a new theory of time - but there are those who are jealous of his work, and will do anything to block him. So he leaves his homeland, hoping to find a place of more liberty and tolerance.
Initially feted, Shevek soon finds himself being used as a pawn in a deadly political game.
With powerful themes of freedom, society and the natural world's influence on competition and co-operation, THE DISPOSSESSED is a true classic of the 20th century.