Negotiation is one of a limited number of decision-making modes whose characteristics, taken as assumptions, are not compatible with most of the theoretical work on negotiation to date. The concession/convergence approach has problems of symmetry, determinism, and power, but above all fails to reflect the nature of negotiation as practiced. Negotiators begin by groping for ajointly agreeable formula that will serve as a referent, provide a notion of justice, and define a common perception on which implementing details can be based. Power makes the values fit together in the package and timing is important to making the formula stick. The article provides examples from cases and experiments are discussed, including the results of a new survey of UN ambassadors using miniscenarios. Finally, the strengths and weaknesses of the formula/detail approach are assessed.