Decay rates and cross sections. The Dirac equation and spin. Interaction by particle exchange. Electron-positron annihilation. Electron-proton scattering. Deep inelastic scattering. Symmetries and the quark model. QCD and colour. The weak interaction and V-A. Leptonic weak interactions. Neutrinos and neutrino oscillations. The CKM matrix and CP violation. Electroweak unification and the W and Z bosons. Tests of the Standard Model. The Higgs boson and beyond.