The Round Table (RT) Talks in Poland in February-April 1989 initiated rapid transition from an authoritarian political system and a centralized, state-controlled economy to democratic capitalism. They also triggered a cascade of changes across the whole of Eastern Europe (the former Soviet block). In this paper I analyze the psychological factors that contributed to success of the talks. During the RT talks, the representatives of the ruling party in Poland („communists”) negotiated with the representatives of „Solidarity” (“democratic opposition”) - the very broad socio-political movement representing Polish aspirations to democracy and sovereignty, separate from the Soviet Union. The paper describes the organization of the negotiations (a complex structure with about 700 participants) and the sources of an initial deep antagonism between the two sides. It addresses the main psychological factors that made it possible for this antagonism to be overcome and for the development of an agreed plan to democratize the Polish political system. This includes an analysis of: the general approach to negotiations; the initial definitions of the negotiating situation and the ways in which these definitions changed; the psychological characteristics of the negotiating situation which fostered cooperative attitudes amongst the negotiations, including in particular the role of group forces. The paper also discusses more generally the relationship between psychological factors and objective conditions in achieving (or impeding) positive outcomes to negotiations around entrenched, seemingly untractable, political conflicts.