A general approach to the statistical theory of non-equilibrium processes is given, which is the natural extension of the method of Gibbs ensembles to the non-equilibrium case. Applications are the Quantum Master  Equation, Kinetic Theory, and Linear Response Theory.  Examples are: Radioactive decay; Dephasing of quantum systems  coupled to a bath; Electrical conductivity in plasmas and  condensed systems. The relation to the description of  stochastic processes is considered. Exercises are given.