The study of shock wave theory for hyperbolic and viscous conservation laws is a good starting point for the study of certain aspects of kinetic theory. It offers different perspective and techniques than those coming from statistical mechanics. The main difference is the emphasis on the fluid dynamical phenomena. However, it is also important to realize that kinetic theory offers more than gas dynamics, particularly when it comes to the shock, initial and boundary layers. Also, depending on the physical situations, different fluid dynamics equations are derived from the Boltzmann equation. We will comment on these issues and present some recent results on invariant manifolds for stationary Boltzmann equation.