There are 2 worlds, with is Anarres/anarchist vs Urras/capitalist, and I had problems with the first half of the book being too didactic about that. But we follow the life of a physicist studying Time (simultaneity vs sequency), from childhood through teenage years and on and forth, with the story being narrated following both worlds in different timelines. Things got darker and darker in both worlds, so much so that at some point I felt trapped, and dispossessed myself, and saw no way out, in neither. This book grows on you, what with LeGuin being the master she is with language, sparse, and with unusual perspectives and points of view.