A misleading title for a rather conventional diplomatic history centered on the years between WW II and the Berlin Crisis. Instead of examining the phenomenon of ""the national security state,"" Yergin restricts his scope to the expanded conception of national security that emerged among US policymakers in this period, and attempts to account for it. The idea originated, he argues, in a view of the Soviet Union as a permanent threat to the US based on an ideological interpretation of Soviet motives. This view, formulated most clearly by George Kennan and predominant in the State Department bureaucracy, won out over a policy of Great Power politics and stable spheres of influence that followed from regarding the USSR as a traditional world power. The latter view Yergin ascribes to FDR, and sees as implicit in the Yalta agreements. Without an institutional base, this policy died with Roosevelt. Yergin places more significance upon this policy conflict than is warranted. There never was any real ""peace"" with the Soviet Union that was subsequently ""shattered,"" and it is not obvious that Roosevelt's policy would have led to substantially different relations between the two countries. The claim that the Cold War began only in the last months of the war is difficult to support in the face of Anglo-American policy toward the USSR throughout the war--not to mention Arno Mayer's claim in Wilson vs. Lenin that the Cold War really began more than 20 years earlier. Yergin has amassed a great deal of documentary material, but his interpretive powers are more limited. A disappointing book.