This book contains selected papers of Prof Nambu who is one of the most original and outstanding particle theorists of our time. This volume consists of about 40 papers which made fundamental contributions to our understanding of particle physics during the last few decades.The unpublished lecture note on string theory (1969) and the first paper on spontaneous symmetry breaking (1961) are retyped and included. The book also contains a memoir of Prof Nambu on his research career.Contents: A Note on the Eigenvalue Problem in Crystal StatisticsThe Use of the Proper Time in Quantum Electrodynamics IPossible Existence of a Heavy Neutral MesonParametric Representations of General Green's FunctionsDispersion Relations for Form FactorsAxial Vector Current Conservation in Weak InteractionsA ‘Superconductor’ Model of Elementary Particles and Its ConsequencesDynamical Model of Elementary Particles Based on an Analogy with Superconductivity I (with G Jona-Lasinio)Chirality Conservation with Soft Pion Production (with D Lurié)Infinite MultipletsS-Matrix in Semiclassical ApproximationQuark Model and the Factorization of Veneziano AmplitudeDuality and HadrodynamicsGeneralized Hamiltonian DynamicsStrings, Vortices and Gauge FieldsBCS Mechanism, Quasi-Supersymmetry and the Fermion Massesand other papersReadership: High energy physicists.Key Features:Gives a unique insight into the minds of two men who challenged one of the most cherished paradigms of modern scienceHighlights the personal and social contexts of a major scientific controversy as it developed and was finally resolvedShows how an idea that was heresy eventually became accepted by the scientific community