Thermodynamic picture of the glassy state

A picture for the thermodynamics of the glassy state is introduced. It assu mes that one extra parameter, the effective temperature, is needed to descr ibe the glassy state. This explains the classical paradoxes concerning the Ehrenfest relations and the Prigogine-Defay ratio. As a second feature, the approach connects the response of macroscopic observables to a field chang e with their temporal fluctuations, and with the fluctuation-dissipation re lation, in a generalized non-equilibrium way.