Classical thermodynamics "is essentially a theory of the destruction of structure" but in some ways this theory has to complemented by a theory describing the"creation of structure". For this purpose it is necessary to go beyond equilibrium or the ner equilibrium region described by linear thermodynamics or irreversible processes. The aim of this monograph is precisely to present such a macroscopic theory covering a large range of phenomena starting from equilibrium and including nonlinear situations, convection and instabilities.