Examining information requirements according to the negotiation categories of structure, strategy, procedure, outcome and behavior, this article calls for data on action types, results, and sources; on determinants of target susceptibilities to action types; on blockage and its costs; on issues under consideration, changing proposals and parties' changing positions on issues; on parties' perceived payoffs, and evaluations of win, loss and deadlock; on parties' evaluation of their security points, and efforts to alter security points; on potential tradeoffs; and on available and evolving conceptions of justice.