This is a basic textbook of thermodynamics and statistical physics suitable for a one-semester upper-undergraduate course. This book is based on my lectures read four times since 2009 at Lehman College of the City University of New York. I opted for a conceptually more transparent quantum-mechanical approach to statistical physics dealing with discrete states from the very beginning. Classical statistics appears as a limiting case of quantum statistics or, in some cases, as an alternative approach at the level of a recipe, to make a comparison with the quantum approach. Elements of quantum mechanics that are needed are introduced in the text. For the sake of simplicity, only the most important building elements of thermodynamics and statistical physics are included in this small book. Still, this most important material is considered in great detail and even illustrated by numerical solutions for the magnetic systems in the mean-field approximation and for the Bose- and Fermi gases. This textbook is also suitable for graduate students and researchers who wish to recuperate the basics of thermodynamics and statistical physics before advancing to more specialized topics.
