During the course of these lectures the following topics will be treated: a) The monomer-dimer problem. b) The Takahashi nearest-neighbor gas. c) The one-dimensional Coulomb gas. d) The transfer matrix method and the one-dimensional nearest and next nearest neighbor Ising models. e) The dimer problem on the square planar lattice: Ã The "algebraic" solution, 2° The operator solution. f) The two-dimensional Ising model. g) The Ice problem. h) The KDP model of a ferroelectric, i) The F model of an anti-ferroelectric.