What is the theme in The Captive Mind by Czeslaw Milosz?

One of the underlying themes of the book is the suppression of individualism. This was a known part of the Soviet model, and as a result there was intense resentment on the part of the people who had their creativity and individualism suppressed. This is obvious on the part of the author. Free thinking was not encouraged or tolerated in the people's democracies. The free thinker was considered a reactionary and an enemy of the proletariat. He was considered to have mental problems and was treated as an outcast.