Prophet of doom who saw hell on earth

In 1960, the publication of Herman Kahn's book On Thermonuclear War (OTW) caused a sensation. This formidable nuclear systems analyst from Rand, the US Air Force think-tank, was the first person to spell out in graphic detail what the consequences would be should the US and Soviet nuclear policy of mutual assured destruction (Mad) go hopelessly awry and nuclear war break out between the two superpowers. Kahn's speciality was civil defence against a nuclear attack, and this required him to "think the unthinkable" (which, incidentally, was the title of his second book, published in 1962) - that is to say, he had to estimate the number of casualties a nuclear war would cause. He nonchalantly mentioned casualties in the tens of millions, and this upset the American public, who certainly did not want to think along these lines, just as they had no wish to contemplate their own mortality.

It is a tribute to Kahn that a third of a century after the publication of OTW , a distinguished independent scholar, Sharon Ghamari-Tabrizi, has produced The World of Herman Kahn: The Intuitive Science of Thermonuclear War , a book on Kahn's life, times and writings. This is a thoroughly researched and well-written and argued book - much more readable than either of Kahn's ponderous tomes.

Tabrizi takes the reader back to Kahn's formative years as an analyst, from when he started at Rand in 1948 as Cold War tensions were heightened by the Russians blocking access to West Berlin and the subsequent airlift.

Evidence that the Soviet Union was catching up in the nuclear arms race was provided by its atomic bomb test in 1949 and its H-bomb test in 1953. With the election of Dwight Eisenhower and the end of the Korean War in 1953, Harry Truman's "communist containment" strategy gave way to Mad - a policy within which Kahn felt more at home.

Kahn's most notorious concept was the Doomsday Machine, the ultimate extension of Mad philosophy. His idea was that it would be technically feasible to link a giant computer to thousands of nuclear missiles so that if the Soviets launched a surprise nuclear attack on the US, the Doomsday Machine would fire its weapons and all life on earth would be extinguished.

It was this idea that stimulated Stanley Kubrick's film Dr Strangelove, or How I Learned to Stop Worrying and Love the Bomb . In the film, an insane commander launches a squadron of nuclear bombers against the Soviet Union.

The Pentagon can recall all the bombers save one, and one is enough to trigger the Doomsday Machine. After the film's release, Kahn, to his great annoyance, became known as Dr Strangelove.

My only major criticism of the book is that the author could have usefully spent more time comparing and contrasting the nuclear threat at the height of the Cold War with that of today. For example, in 1961 the Central Intelligence Agency and Strategic Air Command advised President John F.

Kennedy that the Soviet Union had as many as 1,000 operational intercontinental ballistic missiles, whereas in fact it had only four. The similarities to the flawed intelligence on Iraq's weapons of mass destruction in the run-up to the Iraq War are unmistakable.

Today, as in the 1960s, the public does not like to think about nuclear weapons - during the recent UK general election, for example, the subject was hardly mentioned. Yet, 14 years after the end of the Cold War, the US and Russia still have thousands of nuclear warheads, many on hair-trigger alert, and the risk of accidental use is still with us.

William Perry, who served as Defence Secretary under Bill Clinton, has concluded that there is a 50 per cent chance of a nuclear detonation on US soil during the next decade. Another former Defence Secretary, Robert McNamara, is more concerned that al-Qaeda or some other terrorist group will acquire sufficient fissile material to put together its own atomic bomb.

Perhaps we need another Herman Kahn to shake our complacency.

Jack Harris FRS is vice-chairman of British Pugwash.