  In this paper we emphasize some conceptual points related to the kinetic
foundations of relativistic hydrodynamics. We summarize previous work and focus
on the construction of the heat flux from a kinetic theory point of view. A
thorough discussion addressing aspects concerning stability and causality under
linear perturbations, and the construction of an appropriate stress-energy
tensor, in the case of a high temperature (special relativistic) single
component dilute fluid is included.
