I have to say that I didn't enjoy the portuguese translation I have read, so this probably had impact in my reading of this book - which is, actually, not a book, but I'll explain it right away. I understood that there were some mistakes and metaphors that the translator failed to grasp and Aron's writing felt dryer than it actually is in french, Aron's native language. First, the strangeness lies in the fact that "Karl Marx" is a part of Raymond Aron's book "Main Currents in Sociological Thought" and the portuguese publisher decided to divide this chapter from the book and publish it alone. The cover and the way the book is promoted almost promises an autobiography about Marx, the man, but these few pages are far from that. Aron's aim is to point out some essential aspects of marxism and discussing them, but his thought - or, at least, the translation, because, unfortunately, I haven't read the original version - is often messy. The author seems unable to produce a synthesis of his analysis, forgetting about some topics that he had mentioned before; neither he seems worried about that, forging a narrative that seems to me full of ego, except for one or two key moments when Aron refutes himself. If you're a proud marxist, my advice is that you read Aron's work as soon as possible, because it will provide you grounds to question whether Aron is aware that he is biased or not.