Both a comprehensive overview and a treatment at the appropriate level of detail, this textbook explains thermodynamics and generalizes the subject so it can be applied to small nano- or biosystems, arbitrarily far from or close to equilibrium. In addition, nonequilibrium free energy theorems are covered with a rigorous exposition of each one. Throughout, the authors stress the physical concepts along with the mathematical derivations.For researchers and students in physics, chemistry, materials science and molecular biology, this is a useful text for postgraduate courses in statistical mechanics, thermodynamics and molecular simulations, while equally serving as a reference for university teachers and researchers in these fields.