In the last 15 years or so tremendous progress has been made in the field of non-equilibrium statistical mechanics. In particular, several fluctuations theorems have been derived theoretically (and confirmed experimentally) that establish fundamental relations about the statistics of fluctuations in non-equilibrium states. As the field has by now reached a maturity that should also be reflected in a book. As Prof. Evans has been one of the driving figures in these developments, he and his co-authors could provide both a comprehensive overview and a treatment at the appropriate level of detail. There is a huge number of books written on statistical mechanics. However, none of these incorporate the revolutionary ideas contained in the fluctuation, dissipation or relaxation theorems. 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.