I don't know how close the communism in the book compares to 'real' communism, and that's not a topic for this forum. In-book, the 'communism' mostly revolved around needing to consider the needs of others before your own, and following that line of thought to its 'logical' conclusion. There were hints of it in the first book (farmers had their crops confiscated for "redistribution" by one particular ruler), but it became much more blatant in the later books.