The increasingly progress in computer science and information technology allowed to deal further with complex systems and in closer respect with real-world application. This, in turn, has led to suggestion of software agents, which has been, thereafter, widely used. With the increasing interest on software agents, the "Automated Negotiation" has become a very popular topic of research to facilitate negotiation process design and enhance over all outcomes. "Automated Negotiation" could be defined as a complex process by which two or more agents communicate and attempt to achieve a mutually acceptable agreement on some specific matter. Besides developing a bilateral "Automated Negotiation" model between agents within an incomplete information state, this book provides an architecture of such agents ("buyer" or "seller"). To do so, a new offer generation approach of three adaptive families of tactics has been proposed. Finally, with regard to "Big five" personality model and by introducing the cognitive orientations, we have developed a negotiator agent's architecture taking into consideration the effects of the negotiator agent's personality on negotiation process and outcome.