The story structure is that of one man's live, Shivek, told from two different points in time, switching back and forth. The first part are all the years that Shivek lives on Arras (a communist society). Interleaved with this is the tale of Shivek on Urras (a capitalist society). As the tale moves back and forth, you are given insights into the characters.
This is not a light tale, fully immersing itself into literary style science fiction. Many will start, and many simply won't finish it. You must lend yourself to this story, and even reaching the end, the story may not have lent itself to you. It leaves you with as many questions as ambiguities, and nothing in the way of answers.
I cannot deny that the book is brilliantly written and executed, but I also cannot deny that the book often feels dull and heavy, like too much to eat, all of it heavy. To read this novel is a choice, not an obligation. It should not go onto your must read list, but it should go onto your challenge list, and you should have a challenge list for exactly such books.
Completing the novel felt something of a relief, like opening the curtains, letting the world seem bright again.