Getting Together: Building Relationships as We Negotiate, by Roger Fisher and Scott Brown,
Negotiation is a basic means of getting what you want from others. It is back-and-forth communication designed to reach an agreement when you and the other side have some interests that are shared and others that are opposed.
People find themselves in a dilemma. They see two ways to negotiate: soft or hard. The soft negotiator wants to avoid personal conflict and so makes concessions readily in order to reach agreement. He wants an amicable resolution; yet he often ends up exploited and feeling bitter. The hard negotiator sees any situation as a contest of wills in which the side that takes the more extreme positions and holds out longer fares better. He wants to win; yet he often ends up producing an equally hard response which exhausts him and his resources and harms his relationship with the other side. Other standard...
Any method of negotiation may be fairly judged by three criteria: It should produce a wise agreement if agreement is possible. It should be efficient. And it should improve or at least not damage the relationship between the parties. (A wise agreement can be defined as one that meets the legitimate interests of each side to the extent possible, resolves conflicting interests fairly, is durable, and takes community interests into account.)