Yet the benefits of blurred edges can be felt in an intelligent hybrid such as Ruth Brandon's, where the flowering middle European (mainly Hungarian Jewish) genius at Los Alamos during the creation of the atomic bomb is elegantly epitomised in a character called Zsygmond (Zigi) Von Fisher. Zigi is an all-too-charming bounder in his personal life, an incurable power addict, and yet a public convert to pacifism in cold-water Britain. Brandon's narrator is Zigi's niece Miriam, who embarks on his biography with mixed feelings. Zigi's widow, Aunt Fania, says she has burned Zigi's papers and opposes the project. Miriam knows that her own intimate involvement with Zigi will come to light and may ruin her marriage. She is also of the firm belief that "biography is as subjective as any other form of literature, that it must foster the illusion of fact, but there are ways of presenting, selecting, suppressing and juxtaposing which put the subject at the biographer's mercy. Zigi, who has wielded such power in so many lives, is now in Miriam's power. "In the long run we're all dead and in the hands of our biographers," says Miriam.
Her investigations begin in Budapest where a remarkable clique of young physicists was nurtured. In the 1930s they became caught up in the excitement of Rutherford's atom-splitting and migrated via Copenhagen to American shores where they were recruited for the top secret Manhattan Project. Hitler, having turned his nose up at Einsteinian "Jewish physics", ensured that not only was the world's most advanced nuclear brainpower exported into the hands of his enemies, but that he was also unequipped to combat its brainchild.
Brandon brews up paranoia and elation in her Los Alamos setting. She traces post-war British pacifism from left-wing Soho coffee bars to Greenham Common, where Miriam's daughter spends a year in protest. We accompany Zigi to Reykjavik, where Gorbachev insists on an unfixed agenda to ensure that Reagan's input isn't scripted, and the bemused President very nearly talks himself right out of Star Wars.
The balance of political/historical background to amorous and other personal intrigue is about 60-40: Ruth Brandon, who has written four detective stories, knows how to eke out suspense and secrecy in both arenas. The fact that nearly every female character turns out to be one of Zigi's secret conquests gets a bit samey (his personal allure is apparently as incontravertible as nuclear fission). What is more interesting is the curious variety of ways these women learn to live with their emotional fall-out once Zigi has passed on to the next target.
More interesting still is to be taken back, as Miriam puts it, "to that other world, that forgotten world we inhabited so recently. The Atomic Age. Now that it's over, who can believe how all-consuming, how obliteratingly real it was?" And who can believe that the French think they can ignore this history and world opinion to carry on obliterating regardless?