This is a very good film on the Manhattan Project, the building of the atomic bomb. It is especially a faithful adaptation of the book, DAY ONE, by Peter Wyden. Other reviews here have done a good job of description--I will add that it is far superior to the Paul Newman film on the same topic: FAT MAN AND LITTLE BOY.
In addition, this film is a good teaching tool. I used to show clips from the movie to my U.S. History classes, particularly the latter portion of the film where multiple viewpoints are given of the reasons for and against the dropping of the bomb, whether or not it was necessary, and what would be the moral consequences if such a weapon was used. These viewpoints, from the military and civilian leaders in Washington and at Los Alamos, are not conjured up from the mind of some scriptwriter--they are historically accurate.
In addition, this film is a good teaching tool. I used to show clips from the movie to my U.S. History classes, particularly the latter portion of the film where multiple viewpoints are given of the reasons for and against the dropping of the bomb, whether or not it was necessary, and what would be the moral consequences if such a weapon was used. These viewpoints, from the military and civilian leaders in Washington and at Los Alamos, are not conjured up from the mind of some scriptwriter--they are historically accurate.