The stability of homogeneous thermodynamic equilibrium is analyzed in heat conduction
theories in the framework of nonequilibrium thermodynamics, where the internal energy,
the heat flux and a second order tensor are thermodynamic state variables. It is shown,
that the thermodynamic conditions of concave entropy and nonnegative entropy production
can ensure the linear stability. Various special heat conduction theories, including
Extended Thermodynamics, are compared in the general framework.
