The United States and Japan are the two largest democracies in today's world. The United States is still a superpower economically, militarily, and intellectually, but its traditional independence has changed to a position that requires cooperation and mutual understanding with its major allies and especially with Japan. Japan, also an economic super-power, enormously rich in human, economic, and intellectual resources, but very weak in natural resources, has an equal need for cooperation, military support, and teamwork on all levels. Both nations accept an obligation to contribute their resources fully toward the solution to the world's problems. Consequently, new forms of dialogues and new instruments of cooperation must be devised based on a sophisticated, mutually agreed upon data base. These discussions from the Fourth Shimoda Conference (September 1-4, 1977) explore some of those new directions.