Preface; Part I. The Road to Unification: 1. The electromagnetic current and its properties; 2. The weak currents; 3. The quark model; Part II. Field Theories with Global or Local Symmetries: 4. Yang–Mills theories; 5. Spontaneous breaking of symmetries; 6. Construction of the model; 7. The Higgs mechanism in the Glashow–Salam–Weinberg model; 8. The leptonic sector; 9. Incorporating hadrons; Part III. Experimental Consequences and Comparisons: 10. Deep inelastic scattering; 11. Charged current reactions; 12. Neutral currents in semileptonic reactions; 13. Physics of neutrinos; 14. Heavy quarks; 15. CP violation: K mesons; 16. CP violation: D and B mesons; 17. Higgs particles; Epilogue; Appendix A. Conventions, spinors, and currents; Appendix B. Cross sections and traces; Appendix C. Identities for quark bilinears; Index.