While the experimental study of negotiation groups is of comparatively recent origin, interest in bargaining, negotiation, diplomacy and related processes is long-standing. In the first chapter we shall examine the traditional usage of these terms in the field of international relations and their more recent usage by students of conflict research. In the most general sense, ‘bargaining’, ‘negotiation and ‘diplomacy’ have all been employed to indicate the process whereby parties with conflicting aims establish on what terms they will cooperate. Reliable distinctions between the three concepts are difficult to discern. However, we suggest that to qualify as a negotiation a conference must (a) be a decision-making group, (b) contain members with differing views about what is an acceptable decision, (c) permit a battle of wits between opposing strategists, and (d) undertake discussion before action is taken. Additionally, it is appropriate to distinguish between negotiation and quasijudicial means of determining decisions, like arbitration. Negotiation is ultimately defined as ‘any form of verbal communication, direct or indirect, whereby parties to a conflict of interest discuss, without resource to arbitration or other judicial processes, the form of any joint action which they might take to manage a dispute between them’. When negotiators are intent on securing agreement, we suggest that the term ‘bargaining’ is appropriately used.