Based on the Gibbs maximum-entropy formalism, this statistical mechanisms text offers a foundation for the development of thermal physics, both macroscopic and statistical. Presenting general entropy-maximizing variational principles for thermostatics and equilibrium statistical mechanics, the book also covers modern topics of phase transitions, critical phenomena, renormalization, interacting systems and more. A solid foundation and introduction to modern topics at the forefront of current research is featured together with a commentary section including a range of cultural, technical and historical topics.