A thoughtful prognosis on the future of international relations in the 1970's, a period in which Buchan foresees political influence distributed between a pentarchy of Great Powers comprising the U.S., Russia, Western Europe, China and Japan. The era of American dominance and the Cold War is definitely a thing of the past and Buchan, a veteran British foreign affairs analyst, is hopeful that the new system will be characterized by a greater degree of pragmatism and fluidity, exclusive ""spheres of influence"" (e.g. Latin America, Southeast Asia and the Middle East) giving way to ""accessibility"" and mutual economic ""interpenetration"" in all parts of the world. Buchan believes that the new multiple power balance will resemble the classic 18th-century state system and the Concert of Europe, which prevailed in the 19th century under Metternich, raised to a global scale. Conceding that diplomacy in such balancing eras tends to resemble ""a cynical chess game,"" Buchan suggests that the greater world security gained will be worth the sacrifice of a little idealism: with luck the '70's and '80's will be less prone to brinkmanship and confrontation politics such as the Cuban Missile Crisis. Breaking down the power monolith into four ""instrumentalities"" -- (1) strategic or nuclear force, (2) conventional military weapons, (3) political influence, and (4) economic strength -- Buchan argues that only the first will remain bipolarized in the coming decade -- and presumably its relative importance will wane. This projection, which certainly accords with the recent rapprochement between China and the U.S. and most recently China and Japan, is not implausible but there is at least one disquieting question which the author fails to raise, much less answer. What will be the fate of the ""Third World""? (Buchan concedes that since the '60's it has lost much of its political leverage and moral sway.) Won't the Have-Nots, the small nations of Asia and Africa, pay the price for the greater mutual accommodation among the Big Five? If so the new coexistence strategy is doomed in the long run -- just as Metternich's alignment of status quo powers against the emergent nationalism of the 19th century was doomed. Published for the Council on Foreign Relations, it has a definite Kissinger cast.