Part I. Preliminaries: 1. The nature of observing nature; 2. Fundamental physics: elementary particles and processes; Part II. The Standard Model: 3. Physics in spacetime; 4. The quark model: combinatorics and groups; 5. Gauge symmetries and interactions; 6. Non-abelian gauge symmetries and interactions; 7. The standard model; Part III. Beyond the Standard Model: 8. Unification: the fabric of understanding nature; 9. Gravity and the geometrization of physics; 10. Supersymmetry: boson-fermion unification; 11. Strings: unification of all foundations of reality; Part IV. Appendices: A. Groups: structure and notation; B. A lexicon; C. A few more details; References; Index.