I first read this book about two years ago and have re-read it several times since. I read the trilogy (Gladiators, Darkness at Noon, Arrrival and Departure) in order and so did this one last and it's the best of the three.
the best thing about it is the way that it pulls apart what drives people to hold certain political views, getting beyond whether they think a certain political philosophy has the correct answers into what psychological factors are at play. why do many people on the Left come from relatively good background when the project of the Left is to improve the lot of the poor and disenfranchised?
it ends with the main character aware that non-political indidents have formed his political outlook, and that his views are as much about his character as about whether he believes in the communist ideology, but he decides in any case that some things are worth fighting for.
well worth reading whether you are political or not if you're interested in what makes political types tick.