Shevek, a brilliant physicist, decides to leave his home planet Anarres and travel to Urras to work on his theories of time travel with other physicists. Not only does he leave his family, he leaves his world, a Utopian society that was created centuries ago by anarchists who left Urras in the hope of creating an ideal world where people leave their egos and work for the good of the entire planet. By alternating chapters that describe his new life on Anarres with chapters that flashback on his old life on Urras, Le Guin compares two opposite societies - one capitalistic and similar to today's society in the US and the other a communist colony where people give up homes, possessions, and even the notion of a family for the good of the collective. What I liked about this book is that LeGuin is not preaching one form of society over the other. Both civilizations have some pretty major flaws and both suffer from many of the same issues. She brings up many good points without preaching. Very thought provoking.