A thermodynamical theory for nonequilibrium systems

We present "physical theory" for a certain class of thermodynamic systems out of equilibrium, which is founded on and supported by the analysis of a large family of stochastic microscopic models. We describe the non-equilibrium stationary states, and the non-equilibrium free energy of the system. and we examine the situation in which a stationary state is driven to another stationary state by varying the external parameters on the macroscopic time scale.