1. Introduction : the ways of nature -- 2. Geometry -- 3. Classical physics in Galilean and Minkowski spacetimes -- 4. General relativity and gravitation -- 5. Quantum theory -- 6. Second quantization and quantum field theory -- 7. Relativistic wave equations and field theories -- 8. Forces, connections and guage fields -- 9. Interacting relativistic field theories -- 10. Equilibrium statistical mechanics -- 11. Phase transitions -- 12. Unified gauge theories of the fundamental interactions -- 13. Solitons and so on -- 14. The early universe -- 15. An introduction to string theory.