In this classic text, Fisher and Ury describe their four principles for effective negotiation. They also describe three common obstacles to negotiation and discuss ways to overcome those obstacles. Fisher and Ury explain that a good agreement is one which is wise and efficient, and which improves the parties' relationship.
Wise agreements satisfy the parties' interests and are fair and lasting.
The authors' goal is to develop a method for reaching good agreements. Negotiations often take the form of positional bargaining. In positional bargaining each part opens with their position on an issue. The parties then bargain from their separate opening positions to agree on one position. Haggling over a price is a typical example of positional bargaining.