1. Photons and the Electromagnetic Field -- 2. Lagrangian Field Theory -- 3. The Klein-Gordon Field -- 4. The Dirac Field -- 5. Photons: Covariant Theory -- 6. The S-Matrix Expansion -- 7. Feynman Diagrams and Rules in QED -- 8. QED Processes in Lowest Order -- 9. Radiative Corrections -- 10. Regularization -- 11. Weak Interactions -- 12. A Gauge Theory of Weak Interactions -- 13. Spontaneous Symmetry Breaking -- 14. The Standard Electro-Weak Theory -- Appendix A The Dirac Equation -- Appendix B Feynman Rules and Formulae for Perturbation Theory.