«Enola Gay
Is mother proud of Little Boy today?»
There is an excellent account of Oppenheimer's relation to the bomb in D. Bohm's interview:[1]
at that point of time it didn't seem worse than the fire-bombing of Tokyo. Actually, if you see pictures of the destruction caused in Tokyo by ordinary fire-bombing, these do not look all that different.
This is also De Gaulle's viewpoint as related by Peyrefitte in C'était de Gaulle.
The best account of the bomb in literature is Vonnegut's Cat's Cradle: «‘See the cat’s cradle? See where the nice pussycat sleeps? Meow. Meow.’» It is difficult for the rest of us to see much of anything in how the World goes about its business.