Agents inhabit environments containing other agents. These agents interact in a variety of circumstances. Just as an agent has to tradeoff its own goals under time constraints, multiple agents in such shared environments have to tradeoff goals with others because of resource constraints and goal conflicts. On the other hand, agents can engage in fruitful dialogue by which they can unearth new possibilities and form new productive partnerships. Negotiation is a process by which agents interactively settle on mutually agreeable behaviors to serve common purpose.