  The concept of entropy in nonequilibrium macroscopic systems is investigated
in the light of an extended equation of motion for the density matrix obtained
in a previous study. It is found that a time-dependent information entropy can
be defined unambiguously, but it is the time derivative or entropy production
that governs ongoing processes in these systems. The differences in physical
interpretation and thermodynamic role of entropy in equilibrium and
nonequilibrium systems is emphasized and the observable aspects of entropy
production are noted. A basis for nonequilibrium thermodynamics is also
outlined
