Which is fine, so long as one realizes (pace many) that it's no more than an entertainment. Half a century ago Los Alamos was not just another US Army base, but the focal point of the century, if not of all the centuries since Galileo, where most of the rays crossing this strange and terrible time converged and then came away carrying the image of total destruction, of the most serious moral dilemmas ever to confront humanity and its rulers, dilemmas still with us. In the face of that event, so awful in all senses of the word, devoting one's energies to a fairly standard love-adultery-and-personal-loyalty plot demands either narrative justification (indeed, a really good novelist would seize that point and run with it), or blindness on the part of the author (almost certainly not the case with Kanon), or no ambitions of high seriousness. Now, one could hardly write anything about the Manhattan Project without at least rehearsing the issues: but that's all Kanon does, rehearse them. None of his characters --- not even his Oppenheimer --- really lives them or feels them. Most people in the project did not, of course, spend most of their time worrying about what they were doing and why --- they could hardly have achieved anything if they had --- but from time to time they did, and in any case intensification and distortion are of the essence of art. Kanon does not botch writing a serious novel of ideas about Los Alamos; he doesn't even try.
And wisely so, since that book has already been written, and (adding injury to insult) it's more exciting than Kanon's: I mean of course Richard Rhodes's The Making of the Atomic Bomb, which also happens to be the definitive history. But comparison between the two is unfair, for the historians always have the advantage of novelists. They have but to select and present their facts, to report and to judge. The writers of fiction must make things up as well, and, of necessity, imagination is usually more conventional, less surprising and inventive, than reality. As I said, it's not a fair contest, and the surprising thing is that Kanon managed as well as he did, in a first novel at that: mere mind-candy, but good mind-candy.