The 40-year-old newspapers on my desk chart the terrible plot line, day by day:

On June 20, 450 planes drop 3,000 tons of incendiary bombs on three Japanese cities, leaving behind "one solid mass of flames."

On July 27, 350 planes drop 2,200 tons of firebombs on cities with populations of 377,000.

On July 29, 550 planes drop 3,500 more tons of firebombs.

Finally, on Aug. 6, 1945, a single plane drops a single bomb, the bomb they call "little boy."

In the dry words of The New York Times news summary, "One bomb hit Japan . . . but it struck with the force of 20,000 tons of TNT. Where it landed had been the city of Hiroshima; what is there now has not yet been learned."

It is hard for those of us raised in the nuclear age to imagine what Americans thought when they read the news 40 years ago. I have asked my elders, elders who were younger then than I am now. One, a bombardier who flew over Europe, struggles to remember: "I just thought it was a bigger bomb." Another, a Marine in the Pacific waiting to invade Japan, answers: "I thought, well, I guess I'm going to live."

Still others who read those papers, with eyes glazed by years of war news, must have turned from the news to the ads that bordered it: "Looking forward to fall and a fine fall suit? Come to our third floor and select, in air- conditioned comfort, the wool suit you'll need."

The casualties may have sounded less awesome after four years of death statistics. World War II had already smudged the lines that distinguished soldier from civilian, front line from city. The 130,000 killed those first minutes in Hiroshima may have been more numbers to those already numbed. We did not yet know about skin that peeled off and faces that melted, about radiation sickness and the silent leukemia that struck years, even generations, later. We hadn't yet heard the stories of the hibakusha, the survivors.

Yet in the seamless daily flow of history there was also an abrupt awakening, an immediate, often subliminal, understanding that the bomb had changed everything. Dailiness couldn't dull the early rumblings of existential dread.

The sounds of it were there in Truman's dramatic announcement: "The force from which the sun draws its power has been loosed against those who brought war to the Far East." They were in the solemn cadences in the Vatican's lonely moral judgment: "The last twilight of the war is colored by mortal flames never before seen on the horizons of the universe from its heavenly dawn to this infernal era." They were in the rush to proclaim that this bomb could be a force for good, could portend a new dawn of energy or, at least, a "club for peace."

But now the newspapers have yellowed. Even the microfilm is hard to read. We have learned in intimate detail what happened on the ground at Hiroshima and Nagasaki. Yet in mad competition with the Soviets, we collectively produced some 50,000 bombs that indeed do make the first seem like a "little boy."

The etiquette books tell us to give rubies for a 40th anniversary. But we have given far more than that in this bondage of two generations. We have given the wealth of nations to the bomb. We have sacrificed peace of mind.

On this Aug. 6, in Washington and Moscow, men will get up, eat breakfast, kiss their families goodbye and go to the office to spend the day at nuclear-war games. Diplomats will argue: how many bombs are enough? Who has more?

And all across the world, people who may not be able to explain fission, people who cannot imagine an argument that would justify extinction, will for a moment think about Harry Truman's "rain of ruin" and nuclear winter. They'll remember that the mushroom shape of their deepest fears first rose 40 years ago over a place called Hiroshima. They will surely wonder why, in all these years, those who lead the superpowers have done nothing, absolutely nothing, to still that fear.