Critical phenomena and scale invariance.- Invariance properties of the renormalization group.- Scale transformations in dynamic models.- Critical dynamics in fokker-planck formalism.- Dynamic critical phenomena and the renormalization group — Application to a Lattice dynamic model.- The algebraic approach.to quantum statistical mechanics. Equilibrium states and hierarchy of stability.- Theorems on phase transitions with a treatment for the Ising model.- Statistical mechanics of equilibrium systems: Some rigorous results.- Probabilistic aspects of critical fluctuations.- The application of renormalization group techniques to quarks and strings.- The role of spontaneous broken symmetry.