So did anyone learn to love the bomb?

On Robert Oppenheimer's centenary, Graham Farmelo traces the bombast, betrayals and ethical dilemmas of a nuclear century.

The unexpected discovery of nuclear fission on the eve of the Second World War must count among the most fateful coincidences in human history. Within a few months of the discovery, backroom scientists were drawn from the familiar tranquillity of their offices and labs into an alien world of warfare, secrecy and power politics. The stakes could not have been higher, nor could the nuclear work be more troubling to their consciences: physicists and chemists who had been harmlessly investigating the structure of matter found themselves working with the military to make weapons that politicians could use to kill tens of thousands of people in an instant.

Of all the scientists involved in the early development of nuclear weapons, one stands out as the most important and most intriguing - J. Robert Oppenheimer. When the US government was looking for the right person to lead what became known as the Manhattan Project, they were attracted to Oppenheimer's occasional charm and his academic brilliance, though they must have worried about his leftist beliefs, his prickliness and a history of psychiatric instability. His management skills were unequal to the challenge of managing a hamburger stall, one of his colleagues remarked. Yet Oppenheimer went on to do a remarkably effective job of leading the technical development of the project, only later to be humiliatingly stripped of his security clearance after a McCarthyite inquiry.

Oppenheimer was born 100 years ago. His centenary was celebrated last month at the Institute for Advanced Study in Princeton, which he directed from 1947 until the year before his death in 1967. During the centennial event, Freeman Dyson, a colleague of Oppenheimer at the institute, spoke warmly of his achievement but - like so many others - found his behaviour puzzling.

Dyson believes that Oppenheimer's greatest achievement was the prediction of black holes, yet Oppenheimer was not interested in discussing this work or in whether these holes existed. Dyson suggests that his restlessness prevented him from achieving his great potential as a physicist, though it did allow him to "slide into the role of the good soldier".

The theme of David C. Cassidy's superbly researched biography of Oppenheimer mirrors that of his country in the 20th century. Cassidy, a historian of science at Hofstra University in New York, writes that "the trajectory of (Oppenheimer's) life closely followed the trajectory of America's rise from a provincial, immigrant farming nation to the dominant economic cultural and military power in world affairs". This is a strong idea and Cassidy explores it with erudition.

He follows the life chronologically, from Oppenheimer's upbringing in an affluent New York family to his declining years, when he was revered by his colleagues but sidelined by the political establishment (though he was officially rehabilitated by the order of President Kennedy in 1963, on the day Kennedy was shot). As Cassidy has chosen to focus on the geopolitical significance of his subject's life, it is perhaps not surprising that we hear relatively little of Oppenheimer's artistic influences and of his painful family life. The unfortunate consequence is that we learn rather too little about his passion for poetry, Eastern religion and mysticism, and about the relationship with his alcoholic wife and their children (his son left home to live with his uncle, his daughter killed herself).

There is, however, no doubt that Cassidy gives us a valuable perspective on Oppenheimer's life. The author is shy neither of editorialising nor of making judgements about the personalities who appear in the story and their political circumstances. These comments are almost unfailingly fair and thoroughly justified by the evidence. For example, he has no qualms about saying (more than once) that Oppenheimer was "a fellow-travelling humanist", and that he behaved with deplorable disloyalty to some of his colleagues after the Manhattan Project, behaviour that was to be highlighted in the security hearings that, however, gave Oppenheimer "no chance of a fair hearing".

Two of the book's greatest strengths - its author's integrity and the breadth of his scholarship - perversely lead to its one irritating idiosyncrasy. Cassidy is so keen to credit his fellow biographers and scholars that he mentions them rather too frequently, detracting from the book's otherwise exemplary readability. One paragraph begins: "As described in detail by Pais, Kragh, Schweber, Darrigol, Rueger and others." Wouldn't a simple reference have sufficed?

Overexplicit referencing is certainly not an issue with Peter Goodchild's biography of the man often perceived to be Oppenheimer's nemesis, Edward Teller. The text of the book has no numbered references, although all the quotations are sourced and some additional points are discussed in the notes and references at the back. (This increasingly popular practice is supposed to improve a book's readability, but it is vexatious for a reader who comes across an interesting point in a text and has to turn to the back of the book in the frequently dashed hope that the author has chosen to give more detail about it.) Goodchild, formerly a successful television producer, has written a conventional account of Teller's life, eschewing explanations of his impressive scientific achievements and focusing strongly on his public life. There is not a great deal of revelatory information here, though Goodchild has done his research and has met Teller and some of his close family and friends, allowing him to shed valuable light on his subject's controversial character. Like Cassidy's biography, this features a good deal of well-informed and fair authorial comment, although its scholarly foundations are not quite as solid.

That said, there can be no doubt that Goodchild has produced a compelling narrative, one that enables us to understand how Teller came to be seen by many as a monster. The story begins in prewar Budapest, where he was brought up and had a first-rate education alongside many other Hungarians who were to become luminaries as refugees in the US, including John von Neumann, Eugene Wigner and Leo Szilard. All of them had vivid experience of the communist government that ran their country soon after the First World War, a government that Teller despised for its brutality. Like Oppenheimer, Teller became a first-rate physicist but never quite good enough to be ranked among the very best by his peers. Goodchild does a fine job of demonstrating that, contrary to common opinion, underneath his bombast and vanity lay a profound emotional sensitivity. This does much to explain Teller's envy of Oppenheimer's leading role on the Manhattan Project and his fury at being overlooked (in favour of Hans Bethe) as head of the project's theory division.

Likewise, when Oppenheimer was not keen to promote Teller's pet project of developing a hydrogen bomb (originally the idea of Teller's hero, Enrico Fermi), Teller's fury is understandable if none the less deplorable.

Goodchild's account of Teller's testimony at the Oppenheimer security-clearance proceedings is masterly in its narrative force. It is painful to read what Teller had the effrontery to say to Oppenheimer as he walked past him, having ruined his career: "I'm sorry."

With Oppenheimer displaced from his pre-eminence among the science advisers in Washington, Teller took his place. When he was ostracised by most of the physics community, he was deeply hurt and wounded, but utterly unabashed.

What followed makes fascinating, if deeply unpleasant, reading. Goodchild, while impugning neither Teller's integrity nor his courage, draws a ghastly portrait of a nuclear-mad, Communist-hating egotist. It is easy to see how he became part of the inspiration for Stanley Kubrick's Dr Strangelove, although this glorious character also drew from others, including the strategist Herman Kahn and the rocket pioneer Werner von Braun. As Goodchild says in the text, Teller is "a", not "the", Strangelove figure, as the publishers have misleadingly stated in the book's subtitle.

For him, what mattered was not how many people might be killed by a weapon but that the US must always have a weapon more powerful than those of its enemies. Continually promising more than he and others could deliver, Teller championed the hydrogen bomb, nuclear power and the Strategic Defence Initiative ("Star Wars") of the Eighties and won billions of dollars of government funding for research. It is now hard to deny that much of this funding was wasted. But Teller remained a revered figure in many quarters. In August 2003, less than three weeks before he died, he was awarded America's highest civilian award, the Medal of Freedom, by President George W. Bush.

Oppenheimer and Teller have been well served by their latest biographers, Cassidy and Goodchild. The third nuclear biography under review here, by historian Gerard DeGroot of St Andrews University, is not about a person but about a device: the atomic bomb. His book is a brave attempt to write an accessible but scholarly account of the story of nuclear weapons from Rutherford's discovery of the nucleus in 1910 to the present.

DeGroot has been largely successful in his aim. His extremely readable account is a tour de force of storytelling, a compelling panorama of the political, social and moral issues raised by the development of these weapons. DeGroot has the eye of a first-rate journalist for the telling fact and anecdote. He points out that the power of the bomb the Soviets exploded in the Arctic on October 30, 1961, in the depths of the Cold War, was ten times the combined total of all the explosives used in the Second World War. I was also intrigued to learn that President Nixon liked to boast that, by simply making a quick call, he could kill 75 million people in 25 minutes (actually an underestimate).

Among many fine examples of storytelling, I especially admired his account of the aftermath of the dropping of the bomb on Hiroshima and Nagasaki.

Most authors write of the testosterone-fuelled bravado of Oppenheimer and his military commander, General Groves, but DeGroot adds further, unfamiliar brushstrokes. We learn that Manhattan Project workers were given commemorative jacket badges bearing a mushroom cloud, and that the state of New Mexico made the bomb one of its honorary citizens.

However, DeGroot is sometimes a bit glib for my taste. His editor should have blue-pencilled his most toe-curling paragraph opener - "Here comes the science, so pay attention." Occasionally, his determination to present a snappy overview leads to encapsulations that do not do justice to the prevailing quality of his generalisations. For example, it is simplistic to say baldly that when the German theorist Werner Heisenberg was working on nuclear projects with the Nazis, he was simply "playing a game of self-protection". To the extent that his motivations are knowable, they were much more complicated than that.

DeGroot's book becomes thinner towards the end, when it struggles to put contemporary events in perspective. Such are the difficulties of writing a book that tries to give an up-to-date account of a still-evolving and unpredictable subject. Yet despite its shortcomings, the book is an excellent introduction to the history of the nuclear bomb.

Those who cannot get enough of it - and only they - will enjoy 100 Suns, a handsomely produced book of huge photographs of nuclear detonations, all of them accurately annotated. The title is an allusion to a passage in the Bhagavad Gita, which featured in Oppenheimer's much-quoted reaction to the first nuclear explosion: "If the radiance of a thousand suns were to burst forth at once in the sky, that would be like the splendour of the Mighty One. I am become Death, the destroyer of worlds." I doubt whether Oppenheimer would have enjoyed contemplating the thought that his words would be associated with this first example of a nuclear coffee-table book.

Sensitive browsers might be offended by the celebration of the power of the bomb; the only concession to taste is that the sumptuous aesthetic is dominated by the colour black.

If Oppenheimer had lived to see his centenary, he would surely have been relieved that the weapons he helped to build were not deployed again after Hiroshima and Nagasaki. But he would also have seen that it is no longer sensible to argue, as he often did, that if governments possessed weapons of sufficiently enormous power they could not be used. The global political climate is now much more fragmented than Oppenheimer foresaw, and it is not especially difficult for any sufficiently determined group to build at least a small nuclear weapon. Suicidal terrorists are commonplace, and once again powerful governments are whispering about the desirability of small-scale nuclear strikes. Who would now bet against the world seeing at least one such strike before the centenary of nuclear fission in 2038?

Graham Farmelo is senior research fellow, Science Museum, London.