Instead of the traditional adversarial (win-lose) approach (aka positional bargaining), the mutual gains approach is quite similar to principled negotiation (first described by Roger Fisher in his book Getting to YES), where the goal is to reach a sustainable (i.e., lasting) agreement that both parties (or all parties in a multi-party negotiation) can live with and support.
Mutual gains bargaining has been used successfully in such areas as labor-management relations and environmental negotiations.
Some Principles of MGB
Also see