Foreword.- Chapter 1. Radioactivity, the First Puzzles.- The “Uranic Rays” of Henri Becquerel.- Polonium and Radium.- Emanation from Thorium.- The Puzzle is Disentangled.- Consecrations and Mourning: the End of an Era.- Chapter 2. A Nucleus at the Heart of the Atom.- Prehistory of the Atom.- 1897: The Electrons Are in the Atom.- The Scattering of α Particles Makes It Possible to “See” a Nucleus in the Atom.- A Last Ingredient: Moseley Measures the Charge of the Nucleus in the Atom.- Chapter 3. Quantum Mechanics, the Unavoidable Path.- Branching Off.- An Improbable Beginning.- Niels Bohr: The Quanta Are in the Atom.- 1913-1923: Victories and Setbacks.- 1925: Spin and the Pauli Principle.- Quantum Mechanics.- Chapter 4. A Timid Infancy.- The Atomic Nucleus in 1913.- The Discovery of Isotopes and the Measurement of Masses of Nuclei.- An Enquiry Full of Surprises: β Radioactivity.- The First Nuclear Reactions.- The Nucleus in 1920 According to Rutherford.- The Rapid Expansion of Experimental Means.- The Atomic Nucleus in 1930.- Chapter 5. 1930-1940: A Dazzling Development.- The Nucleus: A New Boundary.- The Discovery of the Neutron.- Nuclear Theory After the Discovery of the Neutron.- A New Particle: The Positron.- The Birth of Particle Accelerators.- “Charge Independence” of the Nuclear Force.- The Discovery of Artificial Radioactivity.- The School of Rome.- The Great Exodus of Jewish Scientists Under Nazism.- A Proliferation of Theories: Yukawa, Breit and Wigner, Bohr.- The Death of a Giant: Ernest Rutherford.- Hans Bethe Sums Up the Situation in 1936-1937.- The Fission of Uranium.- Chapter 6. The Upheavals of the Second World War.- A Chronology.- The New Face of Physics After the War.- Chapter 7. The Time of Maturity.- New Experimental Means.- Data Accumulate.- The “Shell” Structure of Nuclei.- Elastic Scattering and the “Optical Model”.- Direct Nuclear Reactions.- A Collective Behavior.- A Unified Model of the Nucleus.- The Nuclear Force.- Nuclear Matter.- Chapter 8. Where the Narrative Ends.- Glossary.- Bibliography of Cited Books.- Index.