pret tone of voice and body language to ensure accuracy. Bargaining and haggling depends on the negotiators’ styles, which can be assertive, analytical, or accommodating. Each style can be more successful when a negotiator uses progressive offers that make the other party think they are getting as much as possible. Black Swans are hidden factors that can completely change the negotiation if discovered and leveraged. A successful negotiation requires thorough and specific preparation for how to proceed with the other party based on all available prior knowledge.