Part I Thermodynamics, Statistical Mechanical Models and Phase Transitions.- Introduction.- Thermodynamics.- Statistical Mechanics.- A Survey of Models.- Phase Transitions and Scaling Theory.- Part II Classical Approximation Methods.- Phenomenological Theory and Landau Expansions.- Classical Methods.- The Van der Waals Equation.- Landau Expansions with One Order Parameter.- Landau Expansions with Two Order Parameter.- Landau Theory for a Tricritical Point.- Landau_Ginzburg Theory.- Mean-Field Theory.- Cluster-Variation Methods.- Part III Exact Results.- Introduction.- Algebraic Methods.- Transformation Methods.- Edge-Decorated Ising Models.- 11 Transfer Matrices: Incipient Phase Transitions.- Transfer Matrices: Exactly Solved Models.- Dimer Models.- Part IV Series and Renormalization Group Methods.- Introduction.- Series Expansions.- Real-Space Renormalization Group Theory.- A Appendices.- References and Author Index.