This book took me years to finish, but in the end it was worth it. It was universally recommended as a good history of the development of the atomic bomb and of the Manhattan Project, but it is slow, slow going for a long time unless you have a working understanding of nuclear physics, which I do not. But the writing is really good, with Rhodes providing memorable character sketches of the numerous important figures in the development of the weapon.
Where I really got interested was when the physicists’ discussions gave rise to a national project to develop an atomic weapon. The efforts to build the massive infrastructure that development of a bomb would require was simply fascinating, and provided a great background for the watching of Fat Man and Little Boy, which dramatizes a portion of that activity. I know the author would hate to hear that his book was a good introduction to a generally panned movie, but it really was.