The beginning is absolutely mesmerizing - looking over the shoulders of Rutherford, of Bohr, of all the greats that developed quantum theory and the theory of atoms. The middle bit dragged a bit for me. I wanted to read the book for the physics and for the life of the physicists, while WWII history is frankly a tad dry for me. The ending of the book, trinity, the bombing of Hiroshima and Nagasaki, is a gripping, cruel end to this marvel of literature.