Eugene Wigner is one of the very few scientists that maysafely be describedas creators of 20th-century physics.This volume of his Collected Works is devoted to hiscontributions to nuclear energy. In his Introduction andAnnotations A.M. Weinberg surveys Wigner's contributions tonuclear-reaction physics and nuclear engineering, at thesame time giving a glimpse of the early history ofnuclear-reactor technology. Wigner himself gave a lively andcritical account, which is published in this volume for thefirst time. Furthermore the book contains forty-two reportsand memoranda from 1941 to 1945 and twelve of Wigner's manypatents relating to nuclear energy.Eugene Wigner is one of the very few scientists that maysafely be describedas creators of 20th-century physics.This volume of his Collected Works is devoted to hiscontributions to nuclear energy. In his Introduction andAnnotations A.M. Weinberg surveys Wigner's contributions tonuclear-reaction physics and nuclear engineering, at thesame time giving a glimpse of the early history ofnuclear-reactor technology. Wigner himself gave a lively andcritical account, which is published in this volume for thefirst time. Furthermore the book contains forty-two reportsand memoranda from 1941 to 1945 and twelve of Wigner's manypatents relating to nuclear energy.I Introduction: Eugene Wigner and Nuclear Energy.- Introduction: Eugene Wigner and Nuclear Energy.- II Memoir of the Uranium Project.- Memoir of the Uranium Project.- III Acrticles, Reports, and Memoranda on Nuclear Energy.- The Pre-Chicago Days Annotation by Alvin M. Weinberg.- 1. For Discussion of the Homogeneous and Lattice Arrangements for Power Plants.- 2. Approximation for Radius of Sphere Sufficient for Chain Reaction in Light Isotype.- 3. Diffusion of Slow Neutrons on Absorbing Materials.- 4. Solution of Boltzmanns Equation for Monoegenergetic Neutrons in an Infinitels