The Theoretical Physics by Eckhard Rebhan, which was initially published in two extensive volumes, now presents Thermodynamics and Statistics in a slimmer single volume, following Mechanics, Electrodynamics, and Quantum Mechanics. Students often find Thermodynamics and Statistics to be challenging. However, they should be essential tools for every physicist, as there is hardly any area of physics where thermodynamic processes do not play a role. While phenomenological thermodynamics is formally simple, it is conceptually somewhat abstract. In contrast, statistical thermodynamics is conceptually clearer but formally significantly more difficult. To create a balance, both areas are developed in close interconnection. Right at the beginning of the book, the most important foundations from probability theory are introduced.