Shattering the Myth of the Bomb : How we tried to control the atom : DARK SUN: The Making of the Hydrogen Bomb, <i> By Richard Rhodes (Simon & Schuster: $32.50; 703 pp.)</i>

The end of America’s confrontation with the Soviet Union has granted scholars access to classified information in both Washington and Moscow that a few years ago they could only have dreamed of. That we can now look on the Cold War in retrospect, as a coherent whole--with a beginning, middle and end--allows the writing of books on large, important aspects of that epoch with a chance that their historical judgments will stand the test of time.

“Dark Sun” is such a book. It demonstrates the same ambition, literary skill, unrelenting research, talent for portraiture, understanding of the links between science, war and politics, willingness to stand up to large historical questions and sound judgment that distinguished Richard Rhodes’ 1988 book, “The Making of the Atomic Bomb.” But this is the more important volume, not only because of its influence on the way we think about a half-century of world history, but because the hydrogen bomb continues to cast a shadow on the world today.

The book interweaves three tales. The first is the American effort to build hydrogen weapons. In February, 1950, Truman privately said, as shown in the diary of his aide Eben Ayers, “that we had to . . . make the [H-] bomb . . . if only for bargaining purposes with the Russians.” In November, 1952, came, in the Pacific, the first successful test of a staged thermonuclear reaction, shifting the course of the world from fission bombs, which, as the physicist Herbert York observed, had been thought “limited in power. Now, it seemed, we had learned to brush even these limits aside and to build bombs whose power was boundless.”

Rhodes’ second tale is the Soviet campaign to catch up with the United States. Using newly opened Soviet archives and other new sources, he is able to show the “long, slow, expensive route” the Soviets took. As Rhodes explains in intimate, lengthy and dramatic detail, Soviet espionage agents in the United States helped. In August, 1949, came a Soviet bomb comparable to the American one dropped on Nagasaki. “Now Stalin had a bomb on his hip,” Rhodes writes, “and the West could no longer blackmail him.” Four years later, at Semipalatinsk, the Soviets tested a layer-cake thermonuclear explosion, after which Andrei Sakharov was told, “Thanks to you, the savior of Russia!”

Rhodes’ third tale is the most vital--how the Americans and Soviets sought to both control the hydrogen bomb and use it for their own political ambitions. It runs from the Joint Chiefs of Staff’s approval of preventive war in the summer of 1945 to the Cuban missile crisis, when that great champion of air power, Gen. Curtis LeMay, urged President John F. Kennedy to h-bomb Cuba and take advantage of the overwhelming American nuclear superiority of the time. If Kennedy had followed LeMay’s advice, writes Rhodes, “history would have forgotten the Nazis and their picayune Holocaust. Ours would have been the historic omnicide.”

Throughout the Cold War, Soviet and American leaders allowed the arms race to divert badly needed resources away from home and to increase the danger of accidental Armageddon, even though they knew that each side would be deterred from general war by a balanced, minimum number of nuclear weapons. Rhodes explains that “efforts at arms limitation foundered not only on Soviet refusal to admit inspection, as cold warriors claim. It also foundered not only on Soviet refusal to admit inspection, as cold warriors claim. It also foundered on the resistance of U.S. hawks. . . . Minimal deterrence was political suicide so long as the Soviet Union existed, as Jimmy Carter learned when he proposed it shortly after his election in 1976.”

Still, Rhodes’ concludes these pages with surprising optimism. For the most part, nuclear weapons are in our past, he writes: They “will never be easy to make, and they are uniquely destabilizing, invoking the deterrent forces of all the major nuclear powers against even local and regional threats.

What nation--whether or not it possessed nuclear weapons of its own--would allow a sub-national group to build them on its territory? Why build a nuclear weapon to blow up the World Trade Center when you can blow it up with nitrate fertilizer and motor oil?”

Above all, science “has gradually removed the prejudice that there is a limited amount of energy available in the world to concentrate into explosives, that it is possible to accumulate more of such energy than one’s enemies and thereby militarily to prevail.”

“Dark Sun” is also available (abridged) read by Richard Rhodes on four audiocassettes from Simon & Schuster ($25).