There is also an excellent documentary called The Day After Trinity. It is IMO well balanced and has interviews with a lot of the physicists who actually worked with Oppenheimer at Los Alamos, and a few who went to Japan after the blasts to document the aftermath.
It is on the Archive: https://archive.org/details/thedayaftertrinity/thedayaftertr...
Also worth mentioning is the BBC podcast The Bomb:
https://www.bbc.co.uk/programmes/p08llv8n/episodes/downloads