This chapter is about negotiation and has three goals. First, we review recent developments in the social psychological study of negotiation. Second, we develop a set of basic principles that covers current insights into the negotiation process and captures cognitive, motivational, and affective influences on the quality of agreements people reach. Third, we develop the idea that to make strategic decisions, individuals in negotiation need to make sense of their situation and their counterpart. That is, to understand negotiation we need to understand how people search and process information and use the emerging insights to make strategic decisions that, ultimately, affect their own as well as their counterpart's outcomes. We begin this chapter with a brief discussion of the structure of negotiation and argue that individuals in negotiation face fuzzy situations that are full of uncertainties and ambiguities and require sense making on the part of the negotiators. We then discuss the strategies and interaction patterns that characterize negotiation and develop principles about strategic repertoires negotiators have, and about action-reaction patterns across different phases of negotiation. In the third section we discuss the negotiator as motivated information processor, concentrating on the (often detrimental) impact of cognitive heuristics, naive realism, and ego defensiveness. In this section we also discuss work showing that the influence of these information-processing barriers may be countered by the epistemic motivation to process information systematically and deliberately. In the fourth section we view the negotiator as social animal, and focus on impression management motives, and the wealth of research on proself versus prosocial motivation, questioning the rather popular assumption that individuals in conflict and negotiation are self-interested and ignorant of their counterpart's needs and desires. In the fifth section we consider the emotional negotiator and discuss the intra- and interpersonal functions of affect and emotion in negotiation. In each of these five sections we identify one or more basic principles of negotiation. To examine the generality of these basic principles and processes, we review in the sixth section recent research on cross-cultural differences in negotiation. We conclude with a summary and integration of the 10 principles identified in this review and provide some general direction for future inquiry. (PsycINFO Database Record (c) 2012 APA, all rights reserved)