Baudrillard's earlier books were attempts to argue that the first two of these values are not simply associated, but are disrupted by the third and, particularly, the fourth. Later, Baudrillard rejected Marxism totally ("The Mirror of Production" and "Symbolic Exchange and Death"). But the focus on the difference between sign value (which relates to commodity exchange) and symbolic value (which relates to Maussian gift exchange) remained in his work up until his death. Indeed, it came to play a more and more important role, particularly in his writings on world events.