The Dispossessed - by Ursula K. Le Guin
The Dispossessed is the spellbinding story of anarchist Shevek, the “galactically famous scientist,” who single-handedly attempts to reunite two planets cut off from each other by centuries of distrust.
Review from Drew: My ex’s favorite book of all time - I just finished it and whole-heartedly agree with her. It’s a science fiction novel about a brilliant physicist who was raised in a utopian anarchist society as he tries to bridge the gap between his world and their sister planet, which looks very much like our own. There are tons of new-paradigm seeds in this story that have planted themselves firmly in my subconscious. And Ursula Le Guin in general is a must-read for any science fiction lover - I’d recommend The Left Hand of Darkness as well.